Escape Anaconda Island has a lock that does not exist in an ordinary number pyramid. It is called River Rise. The river is rising, so every brick holds a little extra water. The rule, in the book's words, is that every brick is the two bricks below it added together plus the rise on the gauge, the same rise all over the board.
The new rule
In a plain pyramid, a brick is left + right. In River Rise a brick is left + right + rise. If the gauge reads 2, every brick gets 2 added on top. The example below is our own, made up for this post, and a bit easier than the book's locks.
When the gauge has no number
The hardest version has a ? on the gauge. Then you must find the rise first. Here the top is 26 and the bottom row is 6, 3 and 8.
What we know
Top 26. Bottom 6, 3, 8. The gauge shows ?.
Add up without the rise
Pretend there is no rise. 6 + 3 = 9 and 3 + 8 = 11. Then 9 + 11 = 20.
What is left over?
The real top is 26. So 26 − 20 = 6 is all the rise there is, added up.
How many rises?
One rise went into each of the two middle bricks, and one more into the top. That is three rises: 6 ÷ 3 = 2. The gauge reads 2.
Climb with the rise
6 + 3 + 2 = 11. 3 + 8 + 2 = 13. Then 11 + 13 + 2 = 26. Perfect.
The counting rule behind it
In a three-row River Rise, the rise is counted three times in the top brick: once in each middle brick, and once in the top. A taller wall counts it more often. The trick to remember is simple: take away everything you know, and what is left is rises, then share it out.
How a page looks in the book
A low-resolution page from Escape Anaconda Island, so you can see the layout. Nothing on it is solved.
Books mentioned
Escape Anaconda Island
A puzzle adventure gamebook along nine locked walkways to the Lookout Pyramid, with 15 kinds of lock and true snake facts. River Rise is one of those 15 locks, so the book is not all of one puzzle.
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