diff --git a/src/Arts.cs b/src/Arts.cs
index 0ae65c6..f44ebec 100644
--- a/src/Arts.cs
+++ b/src/Arts.cs
@@ -80,14 +80,15 @@ static class Arts
         Matrix m4_world = Mono.world_pose.ToMatrix();
         Hierarchy.Push(m4_world);
 
-        // mesh test
-        meshes["_dmg"].Draw(
-            mat_mono,
+        // ground
+        meshes["circle"].Draw(
+            mat_unlit,
             Matrix.TRS(
-                V.XYZ(0, 0, -1),
+                V.XYZ(0, 0, 0),
                 Quat.Identity,
-                0.1f
-            )
+                12.0f
+            ),
+            Color.Hex(0x808080FF).ToLinear()
         );
 
         // bamboo