MathDB

We build a tower of

2\times 1

dominoes in the following way. First, we place

55

dominoes on the table such that they cover a

10\times 11

rectangle; this is the first story of the tower. We then build every new level with

55

domioes above the exact same

10\times 11

rectangle. The tower is called stable if for every non-lattice point of the

10\times 11

rectangle, we can find a domino that has an inner point above it. How many stories is the lowest stable tower?

Problem Statement