Step 3: Cut 154 Lengths of Straw (And Then a Lot Extra)
Each grid will take exactly 154 lengths of straw, unless your drinking straws are some weird non-standard size. I made 2" and 3/4" grids, so that's what I'll describe here.
The 2" long grid casts about a 1 1/2' spot at 6', the 3/4" long grid's spot is a bit over twice that size at the same distance. I haven't exactly measured. Just to be clear, by length I mean how far the light has to travel to pass through the grid, or the length of the straws that make up the grid!
If you have a friend around, have him do the chopping while you hold the straws, that way you can easily cut a bunch at the same time! Hold the straws on both sides of the blade while your volunteer works it, letting you keep them straight and under control. Watch your fingers, kids!
Voila! Square cuts, fast. You'll pile up the cut straws like crazy at this rate. You may actually want to cut the straws into 1/4 straw and 1/10 straw lengths to be frugal and not waste anything, but I wanted any math I had to do later on to be as simple as possible.