Pixel crumbs
"Pixel crumbs" are single placeable pixels added either accidentally or intentionally to large unplaceable areas on the canvas placemap.
A pixel crumb was added to the center of canvas 4.
On canvas 36, a single pixel was accidentally left in the middle of one of the holes in the cheese when the canvas was being designed.
This pixel was referred to as "The crumb" by the community which is where the term "Pixel crumb" originated from.
A spiritual successor to canvas 36's "The crumb" on was added to the very center of canvas 58.