Simple demo of the while block. The bat should animate exercising for 10 seconds (specifically the thought bubble should go 0 -> 10). The implementation for while is here: https://github.com/LLK/scratch-vm/blob/8faad674396c906596e6a678c0c11fa4aa9f1333/src/blocks/scratch3_control.js#L76-L82 (incidentally ive began getting into an actual, if fairly simple exercise routine lately! the bat and i are both making good progress. :'))
