diff --git a/src/deepali/core/flow.py b/src/deepali/core/flow.py
index cea7054..1a5b412 100644
--- a/src/deepali/core/flow.py
+++ b/src/deepali/core/flow.py
@@ -55,11 +55,11 @@ def affine_flow(matrix: Tensor, grid: Union[Grid, Tensor], channels_last: bool =
     return flow
 
 
-def compose_flows(a: Tensor, b: Tensor, align_corners: bool = True) -> Tensor:
-    r"""Compute composite flow field ``c = b o a``."""
-    a = move_dim(b, 1, -1)
-    c = F.grid_sample(b, a, mode="bilinear", padding_mode="border", align_corners=align_corners)
-    return c
+def compose_flows(u: Tensor, v: Tensor, align_corners: bool = True) -> Tensor:
+    r"""Compute composite flow field ``w = v o u``."""
+    u = move_dim(u, 1, -1)
+    w = F.grid_sample(v, u, mode="bilinear", padding_mode="border", align_corners=align_corners)
+    return w
 
 
 def curl(