Place 18 1x1x5 sticks in a 5x5x5 cube so that it is not possible to place a 19th stick in the cube.
The minimum required to block any more is 12: Three sets of 4 laying against mutually perpendicular sides.
This is easily extended to 18
Bottom layer has 4 flat and two standing upright:
Each additional layer has three flat perpendicular to the bottom (GHI becomes JKL etc):
Posted by Jer
on 2017-04-12 14:55:44