I'm attempting to make a schedule for a dart league. There's 12 people who will be grouped in threes for 11 weeks so they can play each other twice.
I don't know if it helps but I made it into a word problem.
Carl has 4 boxes and 12 gerbils.
Each day Carl puts 3 gerbils in each box.
He does this for 11 straight days but no gerbil is in the same box as any other gerbil more than twice.
Numbering the boxes 1 through 4 and the gerbils 1 through 12, show the boxes and gerbils for each day.

If anyone can help I'd appreciate it. Thank you!