Mixing patterns successfully would need to involve the floors and ceiling as well as the walls and shower. Different scales as well. You have a extra large stripe, and a medium scale print, both blue based. You need a large plaid or large print added to the mix. One that brings in some secondary colors other than blue. A bold yellow or pink, which gets repeated in solid rugs and towels. A blue 66/33 plaid for the ceiling with some of that pink or yellow would be perfect.

Hi @User thank you! I'm very interested in what you've said but want to make sure I understand it. Are you suggesting a plaid or print wallpaper in large scale that has 2/3 blue and 1/2 blend of pink and yellow? Very cute; I love that. You mention the ceiling — what would we need to do there to involve it in the successful mixing of patterns? Thank you again!