# Puzzle 58: Double Back

The online qualification tournament for this year’s German Logic Masters is taking place next weekend, authored by Silke Berendes and me. It’s open as a contest to everybody. Let us know on the forum if anything’s unclear in the instruction booklet (the English version hasn’t been proof-read extensively).

Here’s a Double Back puzzle that didn’t make the cut.

# Puzzle 55: Slovak Sums

Here’s another GP preview puzzle. It’s a bit degenerate, but maybe it’s still useful? For this type, there’s a bit more material out there:

Rules Place digits from 1 to 4 in some blank cells, so that each row and column contains each digit exactly once. Clue numbers indicate the sum of orthogonally adjacent digits. The number of circles under a clue number indicates the number of digits involved in this sum. Or see the instruction booklet.

# Puzzle 54: Lakes

The next GP round is coming up the weekend after next; this time it’s Slovakia’s turn. I’m very much looking forward fo this, after a great first round by Serbia. In that contest, I was particularly impressed by the Fillominos, which didn’t seem like they should turn out unique. It’s a bit early to judge this now, but I quite like the approach of multiple puzzles each of a limited set of types that seems to be followed throughout the GP.

For the Slovakian round, one of the less common puzzle types is Lakes (Regionen). I haven’t been able to find many examples, aside from those in the black-and-white matrix of the 2013 WPC Practice Mini-Marathon and the 2013 Beijing WPC. Do you know any more? Here’s one.

Rules Shade some cells, leaving some orthogonally connected regions of unshaded cells, containing one clue each. Clues indicate the size of the unshaded region that they’re a part of.

Or see the instruction booklet.