|figure a b s m n bloc| figure:=DrGeoCanvas new. a:=figure point: 0@0. b:=figure point: 10@0. s:=figure segment: a to: b. m:=figure pointOnCurve: s at: 0.1. bloc:=[:p| |u v t r| u:=1. r:=p point x. v:=r. [(u-v) abs >0.001] whileTrue: [t:=(u+v)/2. u:=t. v:=r/t.]. r@u]. n:=figure point: bloc parent: m. s:=figure locusOf: n when: m. s color: Color blue.