--- a/progs/knight2.scala	Thu Nov 03 00:53:53 2016 +0000
+++ b/progs/knight2.scala	Thu Nov 03 01:05:20 2016 +0000
@@ -28,7 +28,7 @@
 def tour(n: Int)(steps: List[Pos]): List[List[Pos]] = {
   if (steps.length ==  n * n) List(steps)
   else 
-    (for (x <- moves(n)(steps.head); if (!steps.contains(x))) yield tour(n)(x :: steps)).flatten
+    (for (x <- moves(n)(steps.head).par; if (!steps.contains(x))) yield tour(n)(x :: steps)).toList.flatten
 }
 
 //val n = 8