222
222 (8 visible)
222

222
122 (9 visible)
222

222
221 (9 visible)
222

212
222 (9 visible)
222

222
222 (9 visible)
212

222
212 (8 visible)
222

22222
21112 (12 visible, test horizontal bounds)
22222

222
212
212 (12 visible, test vertical bounds)
212
222
etc.