Algodoo

Based on this math problem:
"Is it possible to hang a painting with a string on any number of pins such that removing just one pin can cause the painting to fall?"
Imagine threading a string around 4 hooks in the order shown in the scene:
+A means clockwise around pin A, and -A means counterclockwise
If a +A and -A or +B and -B touch, they cancel eachother out
To remove a pin (say pin C) remove all +C's and -C's and everything else gets cancelled out
I dunno if I explained well
thamks bai