diff --git a/engine-proto/gram-test/Engine.jl b/engine-proto/gram-test/Engine.jl
index 73c5c31..2662a17 100644
--- a/engine-proto/gram-test/Engine.jl
+++ b/engine-proto/gram-test/Engine.jl
@@ -39,7 +39,7 @@ rand_on_shell(shells::Array{<:Number}) = rand_on_shell(Random.default_rng(), she
 
 # === elements ===
 
-point(pos) = [pos; 1; 0.25 * dot(pos, pos)]
+point(pos) = [pos; 0.5; 0.5 * dot(pos, pos)]
 
 plane(normal, offset) = [normal; 0; offset]
 
diff --git a/engine-proto/gram-test/tetrahedron-radius-ratio.jl b/engine-proto/gram-test/tetrahedron-radius-ratio.jl
index ed3ceb0..c284078 100644
--- a/engine-proto/gram-test/tetrahedron-radius-ratio.jl
+++ b/engine-proto/gram-test/tetrahedron-radius-ratio.jl
@@ -65,11 +65,11 @@ guess = hcat(
     1 -1 -1  1  0    0
     0  0  0  0  1.5  0.5
     1  1  1  1 -0.5 -1.5
-  ] + 0.2*Engine.rand_on_shell(fill(BigFloat(-1), 6)),
-  Engine.point([-1, -1, -1] + 0.3*randn(3)),
-  Engine.point([-1,  1,  1] + 0.3*randn(3)),
-  Engine.point([ 1, -1,  1] + 0.3*randn(3)),
-  Engine.point([ 1,  1, -1] + 0.3*randn(3)),
+  ] + 0.0*Engine.rand_on_shell(fill(BigFloat(-1), 6)),
+  Engine.point([-0.5, -0.5, -0.5] + 0.3*randn(3)),
+  Engine.point([-0.5,  0.5,  0.5] + 0.3*randn(3)),
+  Engine.point([ 0.5, -0.5,  0.5] + 0.3*randn(3)),
+  Engine.point([ 0.5,  0.5, -0.5] + 0.3*randn(3)),
   BigFloat[0, 0, 0, 0, 1]
 )
 frozen = vcat(