Read it as 2 cross 3. The cross represents the number of red rods that would form a floor under the green one. Fit the rods under the green one. Then take these three red rods and form a train. Measure the train.
Towers are more than two rods crossing.
They can be any height. This equation 2 x 3 x 4 would be a tower with the red on the bottom, light green crossing on top and the purple on top of the light green. Solve 2 x 3 first equaling 6 and then 6 x 4 equaling 24. Place the longer rod or the dividend above the shorter one, the divisor. Make a train of equal short rods that equal the one long rod.