Like talking to a blank wall

Like talking to a blank wall.
Sent in by @adeptbeth after seeing a tweet by @mickredsun

My maw says “like talking to a blank wall” instead of “like talking to a brick wall” and when you correct her she claims both ways are acceptable. They aren’t. They just aren’t.
— themightyquinn (@mickredsun) January 10, 2020

A mixed idiom made up from

Like talking to a brick wall, and
perhaps: a blank canvas?

Source of this mixed idiom

@mixedidioms https://t.co/Rx4iz2Nex7
— M E McLaughlin (@adeptbeth) January 12, 2020