diff --git a/src/bellows-dxf.js b/src/bellows-dxf.js
new file mode 100644
index 0000000..1d62bc2
--- /dev/null
+++ b/src/bellows-dxf.js
@@ -0,0 +1,566 @@
+'use strict'
+
+/**
+ * @module bellows
+ * @example
+ * const bellows = require('bellows')
+ */
+
+/**
+ * Try it out [in the browser](https://sixteenmillimeter.github.io/bellows/).
+ *
+ * ### Install (node.js)
+ *
+ * First, install dependencies required by 
+ * [node-canvas](https://github.com/Automattic/node-canvas) by following 
+ * the [install instructions](https://github.com/Automattic/node-canvas#installation) 
+ * for your OS.
+ *
+ * ```
+ * git clone https://github.com/sixteenmillimeter/bellows.git
+ * cd bellows
+ * npm install
+ * ```
+ */
+
+const IN = 25.4
+const BLACK = '0,0,0,1.0'
+const RED = '255,0,0,1.0'
+const BLUE = '0,0,255,1.0'
+
+let browser = (typeof module === 'undefined')
+let Drawing
+let fs
+
+if (!browser) {
+    Drawing = Drawing = require('dxf-writer')
+    fs = require('fs')
+}
+
+function line (ctx, rgba, start, end) {
+    /*ctx.strokeStyle = `rgba(${rgba})`
+    ctx.beginPath()
+    ctx.moveTo(start[0], start[1])
+    ctx.lineTo(end[0], end[1])
+    ctx.stroke()*/
+    ctx.drawLine(start[0], start[1], end[0], end[1])
+}
+
+function dash (ctx, rgba, dpi, start, end) {
+    /*ctx.strokeStyle = `rgba(${rgba})`
+    ctx.setLineDash([(dpi / IN) * 1, (dpi / IN) * 0.5])
+    ctx.beginPath()
+    ctx.moveTo(start[0], start[1])
+    ctx.lineTo(end[0], end[1])
+    ctx.stroke()
+    ctx.setLineDash([0, 0])*/
+}
+
+function basicShape (ctx, offset, front, back, length) {
+    const frontOffset = Math.round((back - front) / 2)
+    const X = -back / 2 + offset[0]
+    const Y = -length / 2 + offset[1]
+    //sides
+    line(ctx, BLACK, [X, Y], [X + frontOffset, Y + length])
+    line(ctx, BLACK, [X + back, Y], [X + front + frontOffset, Y + length])
+
+    //top+bottom
+    line(ctx, BLACK, [X, Y], [X + back, Y])
+    line(ctx, BLACK, [X + frontOffset, Y + length], [X + front + frontOffset, Y + length])
+}
+
+function taper (back, front, length, pos) {
+	const diff = (back - front) / 2
+	//0, 0 -> length, diff
+	return Math.round((diff / length) * pos)
+}
+
+/**
+ * Generate bellows pattern for cutting and folding.
+ *
+ * @alias module:bellows
+ * @typicalname:bellows
+ *
+ *
+ * @param {Object} 	[options]			Bellows configuration options
+ * @param {Integer} [options.dpi] 		DPI of the image
+ * @param {Integer} [options.pageW] 	Page width in pixels
+ * @param {Integer} [options.pageH] 	Page height in pixels
+ * @param {Integer} [options.frontIW]	Front inner width of bellows in pixels
+ * @param {Integer} [options.frontOW]	Front outer width of bellows in pixels
+ * @param {Integer} [options.frontIH]	Front inner height of bellows in pixels
+ * @param {Integer} [options.frontOH] 	Front outer height of bellows in pixels
+ * @param {Integer} [options.backIW] 	Back inner width of bellows in pixels
+ * @param {Integer} [options.backOW] 	Back outer width of bellows in pixels
+ * @param {Integer} [options.backIH] 	Back inner height of bellows in pixels
+ * @param {Integer} [options.backOH] 	Back outer height of bellows in pixels
+ * @param {Integer} [options.maxLength]	Maximum length of bellows in pixels
+ * @param {Integer} [options.align] 	Vertical alignment adjustment in pixels
+ * @param {Integer} [options.parts] 	Number of parts to split pattern into: 1, 2, or 4
+ * @param {Boolean} [options.key]       Print key on page
+ * @param {Boolean} [options.overlap]   Add overlapping flap between parts
+ *
+ * returns {String}  Base64 encoded png data
+ *
+ * @example
+ * const b = bellows({ parts : 2 })
+ * console.log(b)
+ */
+
+function bellows (options = {}) {
+    let canvas
+    let ctx
+
+    let dpi = options.dpi || 300
+    const MM = dpi / IN
+
+    let pageW = options.pageW || dpi * 8.5
+    let pageH = options.pageH || dpi * 11
+
+    let frontIW = options.frontIW  || Math.round(MM * 40)
+    let frontOW = options.frontOW || Math.round(MM * 50)
+    let frontIH = options.frontIH || Math.round(MM * 40)
+    let frontOH = options.frontOH || Math.round(MM * 50)
+
+    let backIW = options.backIW || Math.round(MM * 40)
+    let backOW = options.backOW || Math.round(MM * 50)
+    let backIH = options.backIH || Math.round(MM * 40)
+    let backOH = options.backOH || Math.round(MM * 50)
+
+    let fold = options.fold || (frontOW - frontIW) / 2
+
+    let align = options.align || 0 //adjust the alignment (find formula)
+
+    let maxLength = options.maxLength || MM * 280
+    let parts = options.parts || 2
+
+    let centerX = Math.round(pageW / 2)
+    let centerY = Math.round(pageH / 2)
+
+    let key = (typeof options.key !== 'undefined' && options.key === false) ? false : true
+    let over = (typeof options.overlap !== 'undefined' && options.overlap === false) ? false : true
+
+    let folds = Math.floor(maxLength / fold)
+    let length = folds * fold
+
+    let angleW
+    let angleH
+
+    if (!browser) {
+        //canvas = createCanvas(pageW, pageH)
+        ctx = new Drawing()
+    } else {
+        //canvas = document.createElement('canvas')
+        //canvas.width = pageW
+        //canvas.height = pageH
+    }
+
+    //ctx = canvas.getContext('2d')
+    //ctx.antialias = 'subpixel'
+
+    //fill background white
+    //ctx.fillStyle = 'rgba(255, 255, 255, 1.0)'
+    //ctx.fillRect(0, 0, pageW, pageH)
+
+    //text config
+    //ctx.fillStyle='rgba(0,0,0,1.0)'
+    //ctx.font = '24px Arial'; 
+    //ctx.textAlign= 'start'; 
+
+    function sideW (side) {
+        const frontOffset = Math.round((backOW - frontOW) / 2)
+
+        const X = -backOW / 2
+        const Y = -length / 2
+
+    	let foldIN = X + ((backOW - backIW) / 2) //inside
+    	let foldOUT = X //outside
+    	let t
+    	let t2
+
+        //sides
+        if (side === 1 || parts === 4 || (parts === 2 && side === 3)) {
+        	line(ctx, BLACK, [X, Y], [X + frontOffset, Y + length])
+        }
+        if (parts === 4 && !over) {
+        	line(ctx, BLACK, [X + backOW, Y], [X + backOW - frontOffset, Y + length])
+            for (let i = 1; i < folds; i++) {
+                if (i % 2 === 0) {
+                    if (backIW !== frontIW) {
+                        t = taper(backIW, frontIW, length, i * fold)
+                    } else {
+                        t = 0
+                    }
+                    line(ctx, BLACK, [foldIN + backIW - t, Y + (i * fold)], [foldIN + backIW - t + ((backOW - backIW) / 2), Y + (i * fold)])
+                }
+            }
+        }
+        //inner
+        //line(ctx, BLACK, [X + ((backOW - backIW) / 2), Y], [X + ((backOW - backIW) / 2) + frontOffset, Y + length])
+        //line(ctx, BLACK, [X + backOW - ((backOW - backIW) / 2), Y], [X + ((backOW - backIW) / 2) + frontIW + frontOffset, Y + length])
+        //top
+        line(ctx, BLACK, [X, Y], [X + backOW, Y])
+        //bottom
+        line(ctx, BLACK, [X + frontOffset, Y + length], [X + frontOW + frontOffset, Y + length])
+
+    	//fold lines
+    	for (let i = 1; i < folds; i++) {
+            if (i % 2 === 0) {
+            	if (backIW !== frontIW) {
+            		t = taper(backIW, frontIW, length, i * fold)
+            	} else {
+            		t = 0
+            	}
+            	//fold out
+                line(ctx, BLUE, dpi, [foldIN + t, Y + (i * fold)], [foldIN + backIW - t, Y + (i * fold)])
+            } else {
+            	if (backOW !== frontOW) {
+            		t = taper(backOW, frontOW, length, i * fold)
+            	} else {
+            		t = 0
+            	}
+            	//fold in
+                line(ctx, RED, dpi, [foldOUT + t, Y + (i * fold)], [foldOUT + backOW - t, Y + (i * fold)])
+            }
+        }
+
+        //fold corners, left
+        for (let i = 0; i < folds; i++) {
+        	if (i % 2 === 0) {
+        		if (backIW !== frontIW) {
+            		t = taper(backIW, frontIW, length, i * fold)
+            		t2 = taper(backIW, frontIW, length, (i + 1) * fold)
+            	} else {
+            		t = 0
+            		t2 = 0
+            	}
+            	if (side === 1 || parts > 1) {
+        			line(ctx, BLACK, [foldIN + t, Y + i * fold ], [foldIN - ((backOW - backIW) / 2) + t2, (Y + (i + 1) * fold) ])
+        		} else {
+        			dash(ctx, BLUE, dpi, [foldIN + t, Y + i * fold ], [foldIN - ((backOW - backIW) / 2) + t2, (Y + (i + 1) * fold) ])
+        		}
+        	} else {
+        		if (backIW !== frontIW) {
+            		t = taper(backIW, frontIW, length, i * fold)
+            		t2 = taper(backIW, frontIW, length, (i + 1) * fold)
+            	} else {
+            		t = 0
+            		t2 = 0
+            	}
+            	if (side === 1 || parts > 1) {
+            		line(ctx, BLACK, [foldOUT + t, Y + i * fold ], [foldIN + t2, (Y + (i + 1) * fold) ])
+            	} else {
+            		line(ctx, BLUE, dpi, [foldOUT + t, Y + i * fold ], [foldIN + t2, (Y + (i + 1) * fold) ])
+        		}
+        	}
+        	//
+        }
+        //fold corners, right
+        for (let i = 0; i < folds; i++) {
+        	if (i % 2 === 0) {
+        		if (backIW !== frontIW) {
+            		t = taper(backIW, frontIW, length, i * fold)
+            		t2 = taper(backIW, frontIW, length, (i + 1) * fold)
+            	} else {
+            		t = 0
+            		t2 = 0
+            	}
+        		line(ctx, BLUE, dpi, [foldIN + backIW - t, Y + i * fold ], [foldOUT + backOW - t2, (Y + (i + 1) * fold) ])
+        	} else {
+        		if (backIW !== frontIW) {
+            		t = taper(backIW, frontIW, length, i * fold)
+            		t2 = taper(backIW, frontIW, length, (i + 1) * fold)
+            	} else {
+            		t = 0
+            		t2 = 0
+            	}
+            	line(ctx, BLUE, dpi, [foldOUT + backOW - t, Y + i * fold ], [foldIN + backIW - t2, (Y + (i + 1) * fold) ])
+        	}
+        	//
+        }
+    }
+    function sideH (side) {
+        const frontOffset = Math.round((backOH - frontOH) / 2)
+
+        const X = -backOH / 2
+        const Y = -length / 2
+
+    	let foldIN = X + ((backOH - backIH) / 2) //inside
+    	let foldOUT = X //outside
+    	let t
+    	let t2
+
+        //sides
+        if (parts === 4) {
+        	line(ctx, BLACK, [X, Y], [X + frontOffset, Y + length])
+        }
+        if ((parts !== 1 || side === 4) && !over) {
+        	line(ctx, BLACK, [X + backOH, Y], [X + backOH - frontOffset, Y + length])
+            //cut marks
+            for (let i = 1; i < folds; i++) {
+                if (i % 2 !== 0) {
+                    if (backIH !== frontIH) {
+                        t = taper(backIH, frontIH, length, i * fold)
+                    } else {
+                        t = 0
+                    }
+                    line(ctx, BLACK, [foldIN + backIH - t, Y + (i * fold)], [foldIN + backIH - t + ((backOH - backIH) / 2), Y + (i * fold)])
+                }
+            }
+
+        }
+        //inner
+        //line(ctx, BLACK, [X + ((backOH - backIH) / 2), Y], [X + ((backOH - backIH) / 2) + frontOffset, Y + length])
+        //line(ctx, BLACK, [X + backOH - ((backOH - backIH) / 2), Y], [X + ((backOH - backIH) / 2) + frontIH + frontOffset, Y + length])
+
+        //top
+        line(ctx, BLACK, [X, Y], [X + backOH, Y])
+        //bottom
+        line(ctx, BLACK, [X + frontOffset, Y + length], [X + frontOH + frontOffset, Y + length])
+
+    	//fold lines
+    	for (let i = 1; i < folds; i++) {
+            if (i % 2 !== 0) {
+            	if (backIH !== frontIH) {
+            		t = taper(backIH, frontIH, length, i * fold)
+            	} else {
+            		t = 0
+            	}
+            	//fold out
+                line(ctx, BLUE, dpi, [foldIN + t, Y + (i * fold)], [foldIN + backIH - t, Y + (i * fold)])
+            } else {
+            	if (backOH !== frontOH) {
+            		t = taper(backOH, frontOH, length, i * fold)
+            	} else {
+            		t = 0
+            	}
+            	//fold i
+                line(ctx, RED, dpi, [foldOUT + t, Y + (i * fold)], [foldOUT + backOH - t, Y + (i * fold)])
+            }
+        }
+        
+        //fold corners, left
+        for (let i = 0; i < folds; i++) {
+        	if (i % 2 !== 0) {
+        		if (backIH !== frontIH) {
+            		t = taper(backIH, frontIH, length, i * fold)
+            		t2 = taper(backIH, frontIH, length, (i + 1) * fold)
+            	} else {
+            		t = 0
+            		t2 = 0
+            	}
+                if (parts === 4){
+                    line(ctx, BLACK, [foldIN + t, Y + i * fold ], [foldIN - ((backOH - backIH) / 2) + t2, (Y + (i + 1) * fold) ])
+                } else {
+                    line(ctx, BLUE, dpi, [foldIN + t, Y + i * fold ], [foldIN - ((backOH - backIH) / 2) + t2, (Y + (i + 1) * fold) ])
+                }
+        		
+        	} else {
+        		if (backIH !== frontIH) {
+            		t = taper(backIH, frontIH, length, i * fold)
+            		t2 = taper(backIH, frontIH, length, (i + 1) * fold)
+            	} else {
+            		t = 0
+            		t2 = 0
+            	}
+                if (parts === 4) {
+                    line(ctx, BLACK, [foldOUT + t, Y + i * fold ], [foldIN + t2, (Y + (i + 1) * fold) ])
+                } else {
+                    line(ctx, BLUE, dpi, [foldOUT + t, Y + i * fold ], [foldIN + t2, (Y + (i + 1) * fold) ])
+                }
+        	}
+        	//
+        }
+        //fold corners, right
+        for (let i = 0; i < folds; i++) {
+        	if (i % 2 !== 0) {
+        		if (backIH !== frontIH) {
+            		t = taper(backIH, frontIH, length, i * fold)
+            		t2 = taper(backIH, frontIH, length, (i + 1) * fold)
+            	} else {
+            		t = 0
+            		t2 = 0
+            	}
+        		line(ctx, BLUE, dpi, [foldIN + backIH - t, Y + i * fold ], [foldOUT + backOH - t2, (Y + (i + 1) * fold) ])
+        	} else {
+        		if (backIH !== frontIH) {
+            		t = taper(backIH, frontIH, length, i * fold)
+            		t2 = taper(backIH, frontIH, length, (i + 1) * fold)
+            	} else {
+            		t = 0
+            		t2 = 0
+            	}
+            	line(ctx, BLUE, dpi, [foldOUT + backOH - t, Y + i * fold ], [foldIN + backIH - t2, (Y + (i + 1) * fold) ])
+        	}
+        }
+    }
+
+    function overlap (side) {
+    	const Y = -length / 2
+    	let X
+        let frontOffset 
+        let foldIN 
+    	let foldOUT
+    	let t
+    	let t2
+
+    	let backO
+    	let backI
+    	let frontO
+    	let frontI
+        
+        if (side % 2 === 0) {
+        	X = -backOH / 2
+        	foldIN = X + ((backOH - backIH) / 2)
+        	frontOffset = Math.round((backOH - frontOH) / 2)
+        	backI = backIH
+        	backO = backOH
+        	frontI = frontIH
+        	frontO = frontOH
+        } else {
+        	X = -backOW / 2
+        	foldIN = X + ((backOW - backIW) / 2)
+        	frontOffset = Math.round((backOW - frontOW) / 2)
+
+        	backI = backIW
+        	backO = backOW
+        	frontI = frontIW
+        	frontO = frontOW
+        }
+
+        foldOUT = X
+    	   //sides
+        if (side === 1 || parts === 4 || (parts === 2 && side === 3)) {
+        	//line(ctx, BLACK, [X, Y], [X + frontOffset, Y + length])
+        }
+        line(ctx, BLACK, [X + (backO * 0.3) + ((backO - backI) / 2), Y], [foldOUT + (backO * 0.3) + ((backO - backI) / 2), Y + length])
+        
+        //top
+        line(ctx, BLACK, [X, Y], [X + (backO * 0.3) + ((backO - backI) / 2), Y])
+        //bottom
+        line(ctx, BLACK, [X + frontOffset, Y + length], [foldOUT + (backO * 0.3) + ((backO - backI) / 2), Y + length])
+
+    	//fold lines
+    	for (let i = 1; i < folds; i++) {
+    		if (side % 2 === 0) {
+	            if (i % 2 === 0) {
+	            	if (backI !== frontI) {
+	            		t = taper(backI, frontI, length, i * fold)
+	            	} else {
+	            		t = 0
+	            	}
+	            	//fold out
+	                dash(ctx, BLUE, dpi, [foldIN + t, Y + (i * fold)], [foldIN + (backO  * 0.3), Y + (i * fold)])
+	            } else {
+	            	if (backO !== frontO) {
+	            		t = taper(backO, frontO, length, i * fold)
+	            	} else {
+	            		t = 0
+	            	}
+	            	//fold in
+	                dash(ctx, RED, dpi, [foldOUT + t, Y + (i * fold)], [foldOUT + (backO * 0.3) + ((backO - backI) / 2), Y + (i * fold)])
+	            }
+    		} else {
+	            if (i % 2 !== 0) {
+	            	if (backI !== frontI) {
+	            		t = taper(backI, frontI, length, i * fold)
+	            	} else {
+	            		t = 0
+	            	}
+	            	//fold out
+	                dash(ctx, BLUE, dpi, [foldIN + t, Y + (i * fold)], [foldIN + (backO  * 0.3), Y + (i * fold)])
+	            } else {
+	            	if (backO !== frontO) {
+	            		t = taper(backO, frontO, length, i * fold)
+	            	} else {
+	            		t = 0
+	            	}
+	            	//fold in
+	                dash(ctx, RED, dpi, [foldOUT + t, Y + (i * fold)], [foldOUT + (backO * 0.3) + ((backO - backI) / 2), Y + (i * fold)])
+	            }
+    		}
+        }
+    }
+
+    /*if (key) {
+	    //key
+	    ctx.fillText('Cut lines', dpi / 2, dpi / 2); 
+	    line(ctx, BLACK, [dpi / 2, (dpi / 2) + 10], [dpi, (dpi / 2) + 10]);
+
+	    ctx.fillText('Fold away', dpi / 2, (dpi / 2) + (dpi / 6)); 
+	    dash(ctx, BLUE, dpi, [dpi / 2, (dpi / 2) + (dpi / 6) + 10], [dpi, (dpi / 2) + (dpi / 6) + 10]);
+
+		ctx.fillText('Fold toward', dpi / 2, (dpi / 2) + (dpi / 3)); 
+	    dash(ctx, RED, dpi, [dpi / 2, (dpi / 2) + (dpi / 3) + 10], [dpi, (dpi / 2) + (dpi / 3) + 10]);
+	}*/
+
+    //ctx.translate(centerX, centerY)
+    angleW = Math.atan( (backOW - frontOW) / length) // / (Math.PI / 180)
+    angleH = Math.atan( (backOH - frontOH) / length)
+
+    //SIDES
+
+    //ctx.translate(-backOW - (backOH / 2), 0)
+    //ctx.rotate((angleW + angleH) / 2)
+    sideW(1)
+
+    /*if (parts === 4) {
+        if (over) {
+    	   ctx.translate((backOW / 2) + (backOH / 2) - ( ((backOW - frontIW) + (backOH - frontIH)) / 4 ), align)
+    	   ctx.rotate((angleW + angleH) / 2)
+           overlap(1)
+           ctx.rotate(-(angleW + angleH) / 2)
+    	   ctx.translate(-(backOW / 2) - (backOH / 2) + ( ((backOW - frontIW) + (backOH - frontIH)) / 4), -align)
+    	}
+        ctx.translate(backOW - backIW + (0.3 * backOW), 0)
+    }
+
+    ctx.translate((backOW / 2) + (backOH / 2) - (((backOW - frontIW) + (backOH - frontIH)) / 4), align)
+    ctx.rotate((angleW + angleH) / 2)*/
+    sideH(2)
+    /*
+    if (parts === 4 || parts === 2) {
+        if (over) {
+    	   ctx.translate((backOW / 2) + (backOH / 2) - ( ((backOW - frontIW) + (backOH - frontIH)) / 4 ), align)
+    	   ctx.rotate((angleW + angleH) / 2)
+           overlap(2)
+           ctx.rotate(-(angleW + angleH) / 2)
+    	   ctx.translate(-(backOW / 2) - (backOH / 2) + ( ((backOW - frontIW) + (backOH - frontIH)) / 4), -align)
+    	}
+        ctx.translate(backOH - backIH + (0.3 * backOH), 0)
+    }
+
+    ctx.translate((backOW / 2) + (backOH / 2) - (((backOW - frontIW) + (backOH - frontIH)) / 4), align)
+    ctx.rotate((angleW + angleH) / 2)
+    sideW(3)
+
+    if (parts === 4) {
+        if (over) {
+            ctx.translate((backOW / 2) + (backOH / 2) - ( ((backOW - frontIW) + (backOH - frontIH)) / 4 ), align)
+            ctx.rotate((angleW + angleH) / 2)
+            overlap(3)
+            ctx.rotate(-(angleW + angleH) / 2)
+            ctx.translate(-(backOW / 2) - (backOH / 2) + ( ((backOW - frontIW) + (backOH - frontIH)) / 4), -align)
+        }
+        ctx.translate(backOW - backIW + (0.3 * backOW), 0)
+    }
+    
+    ctx.translate((backOW / 2) + (backOH / 2) - (((backOW - frontIW) + (backOH - frontIH)) / 4), align)
+    ctx.rotate((angleW + angleH) / 2)
+    sideH(4)
+
+
+    if (over) {
+        ctx.translate((backOW / 2) + (backOH / 2) - (((backOW - frontIW) + (backOH - frontIH)) / 4), align)
+        ctx.rotate((angleW + angleH) / 2)
+        overlap(4)
+    }
+
+    return canvas.toDataURL()
+    */
+    return fs.writeFileSync('test.dxf', ctx.toDxfString());
+}
+
+if (!browser) {
+    module.exports = bellows
+}
\ No newline at end of file