Translations:FEM ConstraintDisplacement/27/en

This code has the following syntax:
 * we have 4 variables, the time and all possible coordinates (x, y z)
 * tx is a vector, tx(0) refers to the first variable, the time, while tx(1) refers to the first coordinate x
 * pi denotes $$\pi$$ and was added so that after $$t=1\rm\, s$$ a rotation of 180° is performed