diff --git a/src/xyz/marsavic/gfxlab/graphics3d/scene/SpectrumTest.java b/src/xyz/marsavic/gfxlab/graphics3d/scene/SpectrumTest.java
index 6d6b5ab..66dca30 100644
--- a/src/xyz/marsavic/gfxlab/graphics3d/scene/SpectrumTest.java
+++ b/src/xyz/marsavic/gfxlab/graphics3d/scene/SpectrumTest.java
@@ -23,8 +23,9 @@ public class SpectrumTest extends Scene.Base {
         var materialBlocks = (F1<Material, Vector>) (uv -> Material.matte(0.0));
         var materialUVWallsL = Grid.standard(w -> 1.0);
         var materialUVWallsB = Grid.standard(w -> 1.0);
+        var materialCoverBlock = Grid.standard(w -> 0.0);
 
-        var materialUVWallsR = (F1<Material, Vector>) (uv -> Material.MIRROR);
+        var materialUVWallsR = Grid.standard(w -> 1.0);
 
         var materialGlass = (F1<Material, Vector>) (uv -> Material.GLASS
                 .refractiveIndex(w -> 5.6 + (w-400)/(800-400) * (1.55 - 5.6)));
@@ -40,22 +41,33 @@ public class SpectrumTest extends Scene.Base {
 //                HalfSpace.pn(Vec3.xyz( 0,  1,  0), Vec3.xyz( 0, -1,  0), materialUVWalls),
                 HalfSpace.pn(Vec3.xyz( 0,  0,  1), Vec3.xyz( 0,  0, -1), materialUVWallsB),
                 HalfSpace.pn(Vec3.xyz( 0,  0, -6), Vec3.xyz( 0,  0,  1), materialUVWallsB),
-                Ball.cr(Vec3.xyz(0, 3, 0), 0.8, materialLight),
-                Parallelepiped.pabc(Vec3.xyz(0, 0, 0),
-                        Vec3.xyz(0.4, 0, 0),
-                        Vec3.xyz(0, 0.4, 0),
-                        Vec3.xyz(0, 0, 6),
+                Ball.cr(Vec3.xyz(0, 6, 0), 0.8, materialLight),
+                Parallelepiped.pabc(Vec3.xyz(-0.25, 0, 0.25),
+                        Vec3.xyz(0.6, 0.8, 0),
+                        Vec3.xyz(-0.2, -0.6, 0),
+                        Vec3.xyz(0, 0, -0.5),
                         materialGlass),
-                Parallelepiped.pabc(Vec3.xyz(-5.5    , 1, 1),
-                        Vec3.xyz(4.5, 0, 0),
+
+                Parallelepiped.pabc(Vec3.xyz(-1, 1, 1),
+                        Vec3.xyz(0.75, 0, 0),
                         Vec3.xyz(0, 0.4, 0),
                         Vec3.xyz(0, 0, -6),
-                        materialGlass),
-                Parallelepiped.pabc(Vec3.xyz(0.5, 1, 1),
-                        Vec3.xyz(4.5, 0, 0),
+                        materialCoverBlock),
+                Parallelepiped.pabc(Vec3.xyz(0.25, 1, 1),
+                        Vec3.xyz(2, 0, 0),
                         Vec3.xyz(0, 0.4, 0),
                         Vec3.xyz(0, 0, -6),
-                        materialGlass)
+                        materialCoverBlock),
+                Parallelepiped.pabc(Vec3.xyz(-0.25, 1, 1),
+                        Vec3.xyz(0.5, 0, 0),
+                        Vec3.xyz(0, 0.4, 0),
+                        Vec3.xyz(0, 0, -0.75),
+                        materialCoverBlock),
+                Parallelepiped.pabc(Vec3.xyz(-0.25, 1, -0.25),
+                        Vec3.xyz(0.5, 0, 0),
+                        Vec3.xyz(0, 0.4, 0),
+                        Vec3.xyz(0, 0, -6),
+                        materialCoverBlock)
         );
 
         solid = Group.of(solids);