diff --git a/src/experimental/convex_offset.scad b/src/experimental/convex_offset.scad
index 58d91df5..484bc8fe 100644
--- a/src/experimental/convex_offset.scad
+++ b/src/experimental/convex_offset.scad
@@ -1,21 +1,18 @@
 use <triangle/tri_incenter.scad>;
 
 function convex_offset(vertices, d) = 
-    let(
-	    c = tri_incenter(vertices),
-		leng_vertices = len(vertices)
-	)
+    let(leng_vertices = len(vertices))
     [
 	    for(i = [0:leng_vertices - 1]) 
 	    let(
 		    curr_p = vertices[i],
 			next_p = vertices[(i + 1) % leng_vertices],
-		    v1 = c - curr_p,
+			pre_p = vertices[(i + leng_vertices - 1) % leng_vertices],
+		    v1 = pre_p - curr_p,
 			v2 = next_p - curr_p,
-			leng_v1 = norm(v1),
-			leng_v2 = norm(v2),
-			a = acos((v1 * v2) / (leng_v1 * leng_v2)),
-			leng = -d / sin(a) 
+			a = acos((v1 * v2) / (norm(v1) * norm(v2))),
+			leng = -d * sin(a / 2),
+			v = tri_incenter([curr_p, next_p, pre_p]) - curr_p
 		)
-		v1 / leng_v1 * leng + curr_p
+		v / norm(v) * leng + curr_p
     ];
\ No newline at end of file