p. 653
#1

x0=4;y0=1;x1=28;y1=48;x2=50;y2=42;x3=40;y3=5;

x[t_]:=x0*(1-t)^3+3*x1*t*(1-t)^2+3*x2*t^2*(1-t)+x3*t^3

y[t_]:=y0*(1-t)^3+3*y1*t*(1-t)^2+3*y2*t^2*(1-t)+y3*t^3

sx1[t_]:=x0+(x1-x0)*t

sy1[t_]:=y0+(y1-y0)*t

sx2[t_]:=x1+(x2-x1)*t

sy2[t_]:=y1+(y2-y1)*t

sx3[t_]:=x2+(x3-x2)*t

sy3[t_]:=y2+(y3-y2)*t

ParametricPlot[{{x[t],y[t]},{sx1[t],sy1[t]},{sx2[t],sy2[t]},{sx3[t],sy3[t]}},{t,0,1}]

#3

Manipulate[ParametricPlot[{{4*(1-t)^3+3*a*t*(1-t)^2+3*50*t^2*(1-t)+40*t^3,1*(1-t)^3+3*b*t*(1-t)^2+3*42*t^2*(1-t)+5*t^3},{4+(a-4)*t,1+(b-1)*t},{a+(50-a)*t,b+(42-b)*t},{50+(40-50)*t,42+(5-42)*t}},{t,0,1},PlotRange->{{0,70},{0,70}}],{a,0,70},{b,0,70}]

#4

Manipulate[ParametricPlot[{x0*(1-t)^3+3*x1*t*(1-t)^2+3*x2*t^2*(1-t)+x3*t^3,y0*(1-t)^3+3*y1*t*(1-t)^2+3*y2*t^2*(1-t)+y3*t^3},{t,0,1},PlotRange->{{0,70},{0,70}}],{x0,0,70},{y0,0,70},{x1,-10,100},{y1,-10,100},{x2,-10,100},{y2,-10,100},{x3,0,70},{y3,0,70}]