I was putting the sheet on a mattress for my daughter the other day. The sheet brought back memories. When I was child, about 40 years ago, it was on the bed in the upstairs of my grandparent's house. It took me back to my grandmother reciting evening prayers with my brother and I and tucking us in.
This is the sheet:
The first time I recall drawing the Hubski logo was in high school. I would doodle it on notebooks, and I spray painted it on a graffiti t-shirt I made.
I believe this sheet is the origin.