A friend had a bag to carry equipment for a couples' bowling league, but needed something to keep the balls from rolling all over. I made this so two could be bolted to a thin board with standard 1/4" bolts.

Print it out. Even supporting a bowling ball, it has enough area that it requires very little infill. I used 8%. I had problems with warping when I used a 45 degree infill once it got to the beginning of the 'dish' since it would have bands of solid infill pulling the corners towards each other. If you do the infill at 90 degrees, it goes from the middle of the sides, so the corners can stay planted and square. These are functional rather than for decoration, so I went with a standard 0.27mm layer height at 120 mm/s.