M = moveto
L = lineto
H = horizontal lineto
V = vertical lineto
C = curveto
S = smooth curveto
Q = quadratic Bézier curve
T = smooth quadratic Bézier curveto
A = elliptical Arc
Z = closepath
大写绝对定位，小写相对定位C三次中间两点，Q二次中间一个点
<svg >
<path key={node.y0} d={`M ${node.x} ${node.y} C ${node.x+30} ${node.y} ${node.x0-30} ${node.y0} ${node.x0} ${node.y0}`} stroke="black" strokeWidth="1" fill="none"></path>
<path d={`M 0 0 Q 0 ${position[1].y} ${position[1].x} ${position[1].y}`} stroke="blue" strokeWidth="2" fill="none" />
</svg>
