I think they did that because it's like a bind, i.e. circle 5 <|> rect 8 8 puts a <circle> out first then a <rect> so it seems kind of like the IO monad in that

I think they did that because it's like a bind, i.e. circle 5 <|> rect 8 8 puts a <circle> out first then a <rect> so it seems kind of like the IO monad in that it's ordered