diff --git a/demos/boolean/extrude.geo b/demos/boolean/extrude.geo
index a818edd66efebe1cdca2e3049bb8e6014075f486..2cbe66601c9ee5cf933391b409568457c48473e1 100644
--- a/demos/boolean/extrude.geo
+++ b/demos/boolean/extrude.geo
@@ -29,14 +29,15 @@ Plane Surface(2) = {2};
 Disk(3) = {0.6, 0.6, 0, 0.5, 0.3};
 
 DefineConstant[
-  after = {1, Choices{0,1}, Name "Parameters/Extrude after boolean"}
+  order = {1, Choices{0="Extrude before boolean",1="Boolean before extrude"},
+    Name "Parameters/Operation order"}
 ];
 
-If(after)
-  BooleanFragments{ Surface{1}; Delete; }{ Surface{2:3}; Delete; }
-  Extrude{0,0,0.3}{ Surface{1:5}; }
-Else
+If(order == 0)
   Extrude{0,0,0.3}{ Surface{1:3}; }
   BooleanFragments{ Volume{1}; Delete; }{ Volume{2:3}; Delete; }
   Delete{ Surface{1:3}; }
+Else
+  BooleanFragments{ Surface{1}; Delete; }{ Surface{2:3}; Delete; }
+  Extrude{0,0,0.3}{ Surface{1:5}; }
 EndIf
diff --git a/demos/boolean/revolve.geo b/demos/boolean/revolve.geo
index 8f8ca8062b7bc65039efe62197cf3e59d7e59832..99293b32afb062b3f1ce7514c3e660a65acb3ccb 100644
--- a/demos/boolean/revolve.geo
+++ b/demos/boolean/revolve.geo
@@ -29,10 +29,8 @@ Plane Surface(2) = {2};
 Disk(3) = {0.6, 0.6, 0, 0.5, 0.3};
 
 DefineConstant[
-  angle = {90, Min 0, Max 360, Step 1,
+  angle = {90, Min 1, Max 360, Step 1,
     Name "Parameters/Angle"}
 ];
 BooleanFragments{ Surface{1}; Delete; }{ Surface{2:3}; Delete; }
 a() = Extrude{ {0,1,0}, {0,0,0}, angle*2*Pi/360 }{ Surface{1:5}; };
-
-