With many tramcars in Prague being single-ended each terminus on the network had to have another means of turning the trams. For most of these it was a turning circle but in some cases there was instead a turning triangle. There is now only one remaining triangle and this can be found at Zvonarka which has started to be used more regularly since the introduction of Heritage Line 23 and its fleet of T3 and T3SUCS cars.
* This video was shot by Michael Morton and you can see more of his videos from Prague on YouTube.
I thought I had read the 23 had been, or was being, abandoned due to lack of interest.