A while ago I had a couple perler bead projects that are fairly large. Easily 10000 hand placed beads for each picture. Each plastic square board under bowser holds about 900 beads.
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Yes. They are the plastic beads that you melt. If you squish them enough while melting them, they look square and pixelated. I quickly learned that the melting part is a real challenge with a small iron and a large project. As the beads cool they curl up out of the square racks. I had to hold everything down until they were all attached. Almost effect up bowser.