Hi Peiyao,
The undefined problem comes from your choice Var element not being global and you attempting to access it from outside the parentheses of the corresponding newTrial command. So just make it global when you create it: newVar("choice", 'none').global().log() (don’t forget the pair of parentheses on the log command)
The second problem is a bug in PennController due to the image files being reused across trials. I need to fix it in the next release. In the meantime, just replace ".PennController-left, .PennController-right, .PennController-top, .PennController-bottom" with ".PennController-left-container, .PennController-right-container, .PennController-top-container, .PennController-bottom-container" and your code should work again
Let me know if problems persist
Jeremy