If you only get Z-shapes (of the same orientation) forever, then no. The game's ...

amptorn · on Sept 3, 2017

In fact you can just line five of the Z shapes up along the bottom, over and over again. This technique works indefinitely.

Now, if there's an occasional S shape thrown into the mix, you have a problem.

dwohnitmok · on Sept 3, 2017

As additional clarification if you align the piece upward to look like this then you're fine:

   #
  ##
  #

You'll end up with

   # # # # #
  ##########
  # # # # #

which becomes

   # # # # #
  # # # # #

which you can just repeat over and over again forever (if your variant of Tetris includes gravity even this collapse to nothing).