Let's have a 10x10 grid with 12 empty bases. The rest of the grid is filled with skinny tetrominoes. The 5 regular tetrominoes are marked with a red color and the 2 reflections are marked with a green color. Each base is marked with an orange color.
The following conditions apply:
- The trail has to be continuous.
- The trail is allowed to make only one angle on each square.
- The trail is allowed to pass only once through each square.
- The trail is not allowed to cut any tetromino.
- It is mandatory that each of the the 7 tetrominoes appears a minimum of 3 times.
- The trail must pass through all the bases.
With the above conditions what is the maximum number of squares through which a trail can pass? You can put the bases anywhere you please on the grid.