Puzzle 99: Hochhausblöcke

Hochhausblöcke is a neat skyscraper variant that showed up in the Rätselportal round. They’ve usually been less regular, but from the instructions it was clear that the one on the competition would be an 8×8-grid. I thought there was a good chance of a puzzle without outside clues, and certainly the interactions involved there need more practice, so I tried to construct such a puzzle. I kept running into dead ends, started doubting that they exist at all, and threw the computer at the problem. It turns out that there’s a lot, but they’re rare enough: there’s a good 200000 excluding symmetries, or a little under 1% of all clueless grids you could write down. It should not be unreasonable to find one by hand. Here’s one.


Rules Place numbers from 1 to 4 in each cell so that each row and column of each 4×4-block contains all numbers 1 to 4. Circled numbers are valid skyscraper clues for the adjacent grid (for both adjacent grids in the central corners). Uncircled numbers are not valid skyscraper clues for the adjacent grid (for neither adjacent grid in the central corners).

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s