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docs/lib2x-footprints2.md

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+# footprints2
+
+Drive a turtle with `["forward", length]` or `["turn", angle]`. This function is intended to use a turtle to imitate freehand drawing. 
+
+**Since:** 2.4
+
+## Parameters
+
+- `cmds` : A list of `["forward", length]`s and `["turn", angle]`s.
+- `start` : Set the start point of the turtle.
+
+## Examples
+	    
+	use <polyline2d.scad>;
+	use <turtle/footprints2.scad>;
+	
+	function arc_cmds(radius, angle, steps) = 
+		let(
+			fa = angle / steps,
+			ta = fa / 2,
+			leng = sin(ta) * radius * 2
+		)
+		concat(
+			[["turn", ta]],
+			[
+				for(i = [0:steps - 2])
+				each [["forward", leng], ["turn", fa]]
+			],
+			[["forward", leng], ["turn", ta]]
+		);
+		
+	poly = footprints2(
+		concat(
+			[
+				["forward", 10],
+				["turn", 90],
+				["forward", 10] 
+			], 
+			arc_cmds(5, 180, 12),
+			[
+				["turn", -90],
+				["forward", 10],
+				["turn", 90],
+				["forward", 10],
+				["turn", 90],
+				["forward", 10]
+			]
+		)
+	);
+
+	polyline2d(poly, width = 1);
+
+![t3d](images/lib2x-footprints2-1.JPG)
+