I think it should still be possible, but it will depend a lot on the length of the holes too.<p>If you imagine a really long tube, any light entering at an angle will eventually hit the side, and if the sides do not reflect any light, nothing will come through the tube.<p>I don&#x27;t want to bother doing the math to figure out how big the diameter of the sundial would have to be to have sub-minute accuracy, but I think it is very possible.