Dimension X?

[Jarrah White]

I understand there was no Dimension X in the original comics, only in the old series. Just where did Dimension X originate from?

[Splinter]

It's believed to most likely be taken from the Donatello One-Shot. The Dimensional Gateway that Kirby drew. It looks quite a bit similar to the dimensional portal in the technodrome that led to Dimension X. Beyond that, it's pretty much a creation of the orignal series. :)

[Jarrah White]

I figured as much.