Drag cylinders from the tray onto holes; drop one on an occupied hole to swap, or back into the tray to remove it. While you drag, green dots mark holes that would be conflict-free and the coloured corridors show the band the cylinder occupies in each view. The strips around the board, the camera panels and the checkerboard update live. Page through solved arrangements with ‹ › in the title bar (or ←/→). “Download drilling template (PDF)” prints the checkerboard 1:1 with the pin holes — print at 100 % (actual size), check the 100 mm bar, overlay on the board and drill at the crosshairs.
Holes are addressed (col, row), col along +x (right), row along +y (up), both from 0. Each cylinder is centred on a hole.
A view at angle θ is a camera on the ray at θ (counter-clockwise from +x) looking at the board centre, at cylinder height. Two cylinders are clear in a view when their silhouettes do not overlap and are separated by at least the required gap. Sight-line “corridors” show the band a cylinder occupies in each view.
The solver enumerates every set of hole positions with no conflicting pair, then folds together arrangements that differ only by a rotation or reflection of the board that also maps the view set onto itself.