plot rect((x-1)/2)*[2*asin((x-2)/2)/pi+((x-2)*sqrt(x*(4-x))+2pi)/(2pi)]+rect((x-3)/2)*[2*asin(((-(x-4))-2)/2)/pi+(((-(x-4))-2)*sqrt((-(x-4))*(4-(-(x-4))))+2pi)/(2pi)] from x=0 to 4