Manipulate[Graphics[{{Blue,AbsoluteThickness[1],Line[{{t,1},{t+r Cos[3π/2-t],1+r Sin[3π/2-t]}}]},Line[Table[{s+r Cos[3π/2-s],1+r Sin[3π/2-s]},{s,0,t,.1}]],{Red, AbsolutePointSize[6],Point[{t+r Cos[3π/2-t],1+r Sin[3π/2-t]}]},{Blue,AbsoluteThickness[1],Circle[{t,1},1]}},PlotRange->{{-1.1,4π+1.1},{Min[1-r,0]-.1,Max[2,1+r]+.1}},Axes->{True,False},Ticks->{Table[k π/2,{k,0,12}],None},ImageSize->600,Background->None],{t,0.,4π},{{r,1},{.5,1,1.5,2}}]