Trivial optimization. Wonder if compiler was smart enough about it.
add hedgehog tp svg as reference (as requested by nemo). feel free to improve :P
Fix hedgehogs number desync. Now all desyncs except the one from
issue #521 should be fixed. Please, test.
let's try to kill the thread right away and protect the thread variable with a mutex
I see no reason why a visual effect needs Distance. IMO square should look just fine. Untested. Oh. Also reduced flake count at Randi's request.