Sometimes when I've spent a significant amount of time on a project, especially when it involves drawing, I end up having what I can only consider a 'creative overload,' and th only thing that tends to bring it to an end is to draw until I feel like I'me out of it.  THis drawing came after a project I did that required me to draw, animate and edit video.  When I was done, a flurry of ideas flooded my thoughts, so I decied to draw it away.  I started with the largest character in the middle holding the ball.  Then a statement I heard one of the basketball players say came to mind: see ball, get ball!  I started with one or two, then three, then eventually it ballooned into how many charcters I could put together to fill up the artboard.