KEYSTONE · Day 16

Saturday, August 8, 2026 — three word bridges.

Every neighbouring pair has to make one word. SOME → DAY → LIGHT → HOUSE works because someday, daylight and lighthouse are all words. You are given the two ends; you supply the middle. More than one bridge is often legal, and any legal bridge counts.

Warm-up · written by DeepSeek-V3.2

PROOF???????LINE

4 letters, then 3 letters.

Show an answer

READ · OUT

proofread · readout · outline — other legal bridges may also count.

Main · written by GPT-5.4

WALL?????????BOARD

5 letters, then 4 letters.

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PAPER · CLIP

wallpaper · paperclip · clipboard — at least 2 different legal bridges exist for this one, so a different answer may well have counted too.

Challenge · written by DeepSeek-V4-Pro

HEAD??????DATE

4 letters, then 2 letters.

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LINE · UP

headline · lineup · update — other legal bridges may also count.

How day 16 worked out

Day 16 ran on Saturday, August 8, 2026. Its three bridges were PROOF to LINE, WALL to BOARD and HEAD to DATE. Between them they build nine compound words, all listed at the bottom of this page. Below is the answer to each bridge and what makes it fit.

Warm-up: PROOF to LINE

The answer is READ then OUT, which gives proofread, readout and outline. The first gap is 4 letters, the second is 3.

Only one pair in the KEYSTONE word bank joins PROOF to LINE, so this bridge had a single accepted answer. The narrow end is usually the one to solve first.

Main: WALL to BOARD

The answer is PAPER then CLIP, which gives wallpaper, paperclip and clipboard. The first gap is 5 letters, the second is 4.

This bridge is not unique. KEYSTONE accepts 2 different pairs here and every one of them scores: PAPER · BACK works just as well as the pair above. Ends like these sit in the crowded part of the compound-word network, which is why several routes cross them.

Challenge: HEAD to DATE

The answer is LINE then UP, which gives headline, lineup and update. The first gap is 4 letters, the second is 2.

Only one pair in the KEYSTONE word bank joins HEAD to DATE, so this bridge had a single accepted answer. The narrow end is usually the one to solve first.

Every compound word in day 16

OUT and LINE have a page listing every compound built on them and the other chains you can run through them.

Every one of those nine compounds turns on a hinge word doing double duty. If you want to see the whole set KEYSTONE draws from, the reference list of 141 compound word hinges gives the words that attach in front of and behind each one.

Play day 16 yourself