Maximum number of circles in a large circle or square. Classical “packing” problems. Solved here: http://hydra.nat.uni-magdeburg.de/packing/cci/cci.html.

Circles in circles, black on white, A3

• 19 x 13 (=247) circles filled with circles

Circles in squares, black on white, A3

• 13 x 9 squares filled with a maximum of 117 circles