研习自：[url=https://www.bilibili.com/video/BV1ZW4y1t7VV/?spm_id_from=333.337.search-card.all.click&vd_source=edcad05029f6d4b15eaba8a422397416]【GGB教学】（指令）折线图8-绘制正方体_哔哩哔哩_bilibili[/url]

R=滑动条(0,5,0.01)[br]赋值(R,1)[br]A=(1,1,-1) R[br]B=(-1,1,-1) R[br]C=(-1,-1,-1) R[br]D=(1,-1,-1) R[br][br]l1={A,B,C,D,A}[br][br]f(x)=折线图{0...4,x(l1))[br]g(x)=折线图{0...4,y(l1))[br][br]#缩放[br]p(x)=折线图{0...3,{0,1,1,0})[br][br]#高[br]h(x)=折线图{0...3,{-1,-1,1,1})[br][br][br]a=曲线((f(t),g(t)) p(s)+(0,0,h(s)),s,0,3,t,0,4)[br][br]#可调节,s,0,3.01,t,0,4.01)[br][br]