The four groups
Cache eviction policies
LRU · LFU · FIFO · ARC
LRU/LFU/FIFO are textbook; ARC is the adaptive policy from IBM's 2003 paper.
CPU cache hierarchy
L1 · L2 · L3 · TLB
HTTP caching response directives
ETAG · EXPIRES · NO-CACHE · MAX-AGE
Words that precede HIT
CACHE · BIG · SMASH · COUNTER
Cache hit, big hit, smash hit, counterhit.
Why this puzzle works
The puzzle's title is the bait. CACHE the bare tile is *not* the theme of the puzzle — it's a wordplay tile. NO-CACHE as a single tile is HTTP directive territory. Most playtesters who lose this puzzle do so by trying to make a 'cache things' group from CACHE + NO-CACHE + something else.
How to read a Connectle without solving it
A code-themed grouping puzzle rewards counting as much as recognition. Start by listing every plausible group, then notice which tiles appear in two lists. Whichever group has exactly four unambiguous members is your anchor — solve it first and the rest of the board collapses by elimination. The hardest tier (purple) is almost always wordplay: tiles that share a prefix or suffix, not a concept. If a tile feels orphaned, ask whether the same word could follow or precede a common engineering word like root, stack, cache, or queue.