A feed-design technique, illustrated by early Instagram: crop all user photos to a fixed square rather than preserving each photo's native aspect ratio. Mixing portrait and landscape rectangles in a fixed-width feed forces inconsistent zoom/scaling per item; normalizing every item to one shape at the feed level removes that inconsistency in one move, instead of trying to solve it photo-by-photo. Individual users (Olsen included) were initially annoyed at having their photos cropped, but the fix was deliberate and feed-level, not accidental.
Part of the implementation behind Instagram's 2010 Strategy (Performance + Delighter Case Study).
Apply: When a feed must display heterogeneous content consistently, normalize to a fixed shape at the feed/container level rather than special-casing each content type.