[Dr. Geo] how to fill semicercle or lunulus with DrGeo ?

[address@hidden]

I saved the code below in the DrGeo DrGSmalltalkSketchEditor wizard.

DrGeo is running, in this case, on Cuis 6.3 update #6313.

The version of Cuis was obtained from the World menu with Help -> About this 
system.

Is it possible (and how please, if so) to fill the area of the "lunulus" below ?
The code below is from saving in the DrGSmalltalkSketchEditor.

I tried sending a "filled" message but the arc responds doesNotUnderstand:.

If I fill the semicercle and color it opaque I could perhaps color the 
"lunulus".

|sketch origin triangleLeft triangleRight arcRight arcLeft semiCircle point 
line|
sketch _ DrGeoSketch new.
sketch text:'Lunulus' at:1@1.
sketch gridOn.
sketch axesOn.
origin _ 0@0.
triangleRight _ sketch polygon: { origin. 0@1. 1@0 }.
triangleLeft _ sketch polygon: { origin. 0@1. -1@0 }.
arcLeft _ sketch arcCenter: origin from:0@1  to: -1@0.
arcRight _ sketch arcCenter: origin from:1@0  to: 0@1. 
point _ -0.5@0.5.
line _ sketch segment: origin to:point. 
semiCircle _ sketch arcCenter: point from:0@1  to:-1@0.
arcLeft color:Color red.
semiCircle color:Color red.
triangleLeft filled.


Regards,
David Stes