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diff --git a/.gitignore b/.gitignore
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+*.gcode
+*.stl
diff --git a/README.md b/README.md
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+# gridfinity-scad
+
+[GridFinity](https://gridfinity.xyz/) implementation for [OpenSCAD](https://openscad.org/)
+
+## Example
+
+```scad
+use <gridfinity.scad>
+
+// Arguments are in GridFinity units
+gridfinity(2, 1, 2, lip=true, magnets=false);
+```
diff --git a/example.scad b/example.scad
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+use <gridfinity.scad>
+
+difference() {
+	gridfinity(2, 1, 1, lip=true, magnets=false);
+	translate([21,0,5.2]) linear_extrude(4) rounded_square(78, 36, 0.8);
+}
diff --git a/gridfinity.scad b/gridfinity.scad
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+$fn = 30;
+
+// https://gridfinity.xyz/specification/
+
+height   = 7;
+width    = 42;
+width_tolerance    = 41.5;
+rounding = 3.75;
+
+module rounding(r,angle) {
+	rotate(angle,[0,0,1])
+	translate([-r + 0.01, -r + 0.01])
+	difference() {
+		square([r,r]);
+		circle(r);
+	}
+}
+
+module rounded_square(lx, ly, r) {
+	difference() {
+		square([lx,ly],center=true);
+		union() {
+			translate([ lx/2, ly/2]) rounding(r, 0  );
+			translate([-lx/2, ly/2]) rounding(r, 90 );
+			translate([-lx/2,-ly/2]) rounding(r, 180);
+			translate([ lx/2,-ly/2]) rounding(r, 270);
+		}
+	}
+}
+
+module magnet_hole(h = 0) {
+	linear_extrude(2.5) circle(3.25);
+	translate([0,0,2.5]) linear_extrude(h) circle(1.5);
+}
+
+module base_solid() {
+	hull() {
+		linear_extrude(0.1)rounded_square(35.6, 35.6, 0.8);
+		translate([0,0,0.8]) linear_extrude(1.8) rounded_square(37.2, 37.2, 1.6);
+	}
+	translate([0,0,2.6]) hull() {
+		linear_extrude(0.1) rounded_square(37.2, 37.2, 1.6);
+		translate([0,0,2.15]) linear_extrude(0.1)rounded_square(41.5, 41.5, 3.75);
+	}
+}
+
+module base(magnets = false) {
+	l = 35.6;
+	o = 4.8;
+
+	difference() {
+		base_solid();
+		if (magnets) union() {
+			translate([ l/2 - o,  l/2 - o, -0.01]) magnet_hole();
+			translate([-l/2 + o,  l/2 - o, -0.01]) magnet_hole();
+			translate([ l/2 - o, -l/2 + o, -0.01]) magnet_hole();
+			translate([-l/2 + o, -l/2 + o, -0.01]) magnet_hole();
+		}
+	}
+}
+
+module stacking_lip_negative(ux, uy) {
+	x1 = (width * ux) -5.2 -0.5;
+	y1 = (width * uy) -5.2 -0.5;
+	x2 = (width * ux) -3.8 -0.5;
+	y2 = (width * uy) -3.8 -0.5;
+	x3 = (width * ux) -0.5;
+	y3 = (width * uy) -0.5;
+
+	// translate and scale are here to make sure the negative pokes through
+	// the positive block
+	translate([0,0,-0.001]) scale([1,1,1.001]) hull() {
+		linear_extrude(0.01)rounded_square(x1, y1, 0.7);
+		translate([0,0,0.7]) linear_extrude(1.8) rounded_square(x2, y2, 1.6);
+	}
+	translate([0,0,2.5]) hull() {
+		linear_extrude(0.01) rounded_square(x2, y2, 1.7);
+		translate([0,0,2.15]) linear_extrude(0.01)rounded_square(x3, y3, 3.75);
+	}
+}
+
+function coord_centered(ux) = (ux -1) * width - 0.5 * width * (ux - 1);
+
+module stacking_lip(units_x, units_y) {
+	difference() {
+		linear_extrude(4.4)rounded_square(units_x * width -0.5, units_y * width -0.5, rounding);
+		stacking_lip_negative(units_x, units_y);
+	}
+}
+module gridfinity(units_x, units_y, units_z, lip = true, magnets = false) {
+	for (ux = [0:units_x -1]) {
+		for (uy = [0:units_y -1]) {
+			translate([ux * width, uy * width,0]) base(magnets = magnets);
+		}
+	}
+	if (units_z > 0)
+	translate([coord_centered(units_x), coord_centered(units_y), 4.75]) {
+		extr = units_z * height - 4.75;
+		linear_extrude(extr) rounded_square(units_x * width - 0.5, units_y * width - 0.5, rounding);
+	}
+	if (lip)
+		translate([coord_centered(units_x), coord_centered(units_y), units_z * height])
+			stacking_lip(units_x, units_y);
+}