Moulin means Windmill in French. Rouge is the color red. Moulin rouge means red windmill. The Moulin Rouge in France was a cabaret that really existed until it got burned down.
Hey, we are coslovskiy, a paneuropean art collective and we really wanted to share our vision with you, the genitalia-obsessed fraction of urban dicks:
A mandala rouge basically paints itself when a woman on her period puts on lace lingerie and sits on paper or other printable fabrics and just bleeds for a while.