It's my plastic scrap storage bins!
When I first started sewing, I was shoving all my scraps into one bin which quickly overflowed since I inherited my Grandma Kelley's knack for saving every little thing (including tiny 1-inch square scraps of fabric). I then split the bin into two bins - cool colors and warm colors. This worked for a while, but it was difficult to find specific colors when I needed them. I would end up dumping the entire bin out on the floor to find what I needed.
Hooray for organization!