Infinite Map Zoom Out

[Hypersonic]

1pp is ddt upside down! (the horizontal line in the t blends with the arrow shaft)

https://zdoom.org/wiki/Map_arrow

When you type iddt it cycles through am_cheat 0 (standard arrow) am_cheat 1 (ddt arrow) am_cheat 2 (sprite)

[Gez]

And "ddt" stands for Dave D. Taylor, the man who wrote the automap code (among other things). He used to use a "ddt arrow" as his signature online, as you can see for example on this short text file.