+Allow to navigate in game after it's over (back/play)
For animation, moves should contains "moving" and "fading" maybe...
-Depth 2 or 3 depending on variant and if we detect smartphone or not?
-(static get SEARCH_DEPTH() { return 2; })
+(But it's really just for Magnetic chess)
+setInterval "CRON" task in sockets.js to check connected clients
+(every 1hour maybe, or more)
+Button to show all pieces that can move (next to expert mode; change icons)
+Some bots are very weak, others quite slow...