I've noticed that the typical frag disks or plugs are pretty porous, and it's often tough to pull zoa or paly mats from them without damaging them. however, on the few acrylic plugs I have, they remove easily. This is a big help in fragging. I can simply pull the mat and glue down whatever I want to another disk. I got searching for squares because they will sit tightly to each other and be better for allowing mats to grow across, as opposed to round disks. Here's a link to what I have found...and the price isn't too bad. $0.15 each for 1" squares, .118" thick. Anybody have suggestions, warnings, advice, other sources or options? Plastic Squares : TAP Plastics