In text mode, a pile of items indicates there are more items under the top one by changing the background color.
I understand it is impractical to draw every item in view (especially with up to 4096 items per tile!), so I would like to see a “more” or “pile” tile definition added that does the same thing for tile mode. The “more” tile would display underneath the icon for the top item on the stack and let me know at a glance where piles of loot are.
Maybe a brighter bg?
That could work, but I think a specific tile definition would allow greater flexibility. Tile artists could make it look like a pile or random stuff while less talented folks like me could just draw a funky colored box. If you were dead set on having a brighter bg, you could make your “more” tile a solid #FFFFFF77 square.
Some other Roguelikes’ graphical versions draw extra stuff at a corner of the tile if there’s more than one thing in it.
For instance, Dungeon Crawl draws a ? in the bottom right corner. ToME draws the number of items if >1 (and if >10, draws a *).