This design has nothing to do with the mighty ninja. Instead, it is a found art project with tasty looking beer, wine, and cocktails festooned across bold numbering that reads "21."
I designed it for a cousin who is turning 21. I thought she might enjoy having some gear for the pub crawl we're planning on her 21st birthday. Through a special, limited edition offering, you can now get your own "21" gear for that special ninja in your life who needs an age-appropriate t-shirt.