In the proposed animation, it is possible to choose the value of T expressed in sample number.
The sampling of a function in the time domain is obtained by a multiplication by a Dirac comb function, of period T. This translates itself by a convolution by a Dirac comb function in the frequency domain which introduces a periodisation of period 1/T.

This periodisation can modify the form of the FT of the original signal at low frequencies. This is the case for T=3 or T=4.