<svg width="250" height="250">
<!-- show the path along which the triangle will move -->
<path d="M50,125 C 100,25 150,225, 200, 125"
  style="fill: none; stroke: blue;"/>

<!-- Triangle to be moved along the motion path.
   It is defined with an upright orientation with the base of
   the triangle centered horizontally just above the origin. -->
<path d="M-10,-3 L10,-3 L0,-25z" style="fill: yellow; stroke: red;" >
  <animateMotion
    path="M50,125 C 100,25 150,225, 200, 125"
    rotate="auto"
    keyPoints="0;0.2;0.8;1"
    keyTimes="0;0.33;0.66;1"
    calcMode="linear"
    dur="6s" fill="freeze"/>
</path>
</svg>