diff --git a/Sketch.py b/Sketch.py
index bd669d2..f069950 100644
--- a/Sketch.py
+++ b/Sketch.py
@@ -34,8 +34,8 @@ class Sketch(object):
             e = equations[i]
             coeffs = e[0]
             for c in coeffs:
-                var_index = shape_vars[coeffs[1]]
-                C[i][var_index] = coeffs[0]
+                var_index = shape_vars[c[1]]
+                C[i][var_index] = c[0]
             d[i] = e[1]
         s = SLE(C, d)
         r = s.solve()