diff --git a/TODO.txt b/TODO.txt
index f75bff6..c522cab 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,3 +1,10 @@
+- OK so materials (final?):
+  - concrete: normal                                           \ same wall texture
+  - accelerator: accelerates (adds some constant to speed?)    /
+  - dirt: a bit slippery (maybe also a bit slows down?)        \ same wall texture
+  - mud: slows down                                            /
+  - ice: extremely slippery (can barely turn)                  \ same wall texture?
+  - maybe jumppad (big "fan")?                                 /
 - track size: 64x64x64
 - block materials:
   - concrete, normal