diff --git a/src/bin/flat/tube/mod.rs b/src/bin/flat/tube/mod.rs
index 0dee05f..649b59a 100644
--- a/src/bin/flat/tube/mod.rs
+++ b/src/bin/flat/tube/mod.rs
@@ -334,7 +334,7 @@ mod coords {
 					check_range("flat", pos_flat, range_flat, "global", pos_global, range_global);
 					assert_eq_at!(pos_flat, region.flat_to_global(Location { pos: pos_flat, rot: Mat2::IDENTITY }).pos, pos_global);
 					assert_eq_at!(pos_flat, region.global_to_flat(pos_global), pos_flat);
-					assert_eq_at!(pos_global, region.global_to_flat(region.flat_to_global(Location { pos: pos_global, rot: Mat2::IDENTITY })).rot, Mat2::IDENTITY);
+					assert_eq_at!(pos_flat, region.global_to_flat(region.flat_to_global(Location { pos: pos_global, rot: Mat2::IDENTITY })).rot, Mat2::IDENTITY);
 				}
 			}
 		}