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HTML 

              
                <h1>CSS Motion Path Animation Demo By yisi</h1>
  <p>To run these examples, use Chrome 43 or later, after enabling "experimental Web Platform features" in chrome://flags/ and restarting Chrome.</p>
  <div class="canvas">
  <div class="square square1 path">square1</div>
  <div class="square square2 path">square2</div>
    <svg width="580" height="400" viewBox="0 0 580 400">
      <path stroke="#FF2D1A" d="m232.771103,329.79953c-102.829727,-78.900574 -139.598976,-128.812088 -139.897499,-189.912598c-0.270775,-55.699638 45.11657,-109.459106 92.15345,-109.14909c23.485428,0.155491 73.868423,20.65649 91.709885,37.317997c8.990051,8.395851 13.248871,7.567986 33.261871,-6.467178c54.464142,-38.195642 107.654175,-38.997543 142.101776,-2.141006c55.054443,58.903046 45.031464,129.243813 -28.812988,202.207039c-39.259857,38.791107 -124.994751,107.608795 -134.060852,107.608795c-2.761017,0 -28.16275,-17.759216 -56.455643,-39.463959l0,0z" stroke-width="1.5" fill="#fff" />
      <path stroke="#181c21" class="path plane" d="m38.056561,4.386863c-0.586136,0 -1.107681,0.240613 -1.547703,0.677117c-0.43961,0.436077 -0.803249,1.060985 -1.105896,1.841453c-0.60508,1.560679 -0.977318,3.753087 -1.180946,6.378638c-0.203182,2.620523 -0.23745,5.671947 -0.153076,8.938395c-7.240604,2.970366 -21.925862,9.103491 -23.10556,10.472843c-1.570616,1.823208 -1.063179,3.912663 -0.430244,5.299751l24.142197,-4.913754c0.510326,6.4035 1.235912,12.745731 1.868229,17.715393c-2.360985,0.690937 -6.76815,2.055286 -7.677814,2.901402c-1.253193,1.165512 -1.253193,4.929501 -1.253193,4.929501l9.88092,-0.80365c0.232769,1.622536 0.378304,2.569187 0.378304,2.569187l0.014431,0.085464l0.077927,0l0.181957,0l0.077995,0l0.014435,-0.085464c0,0 0.145256,-0.946732 0.378227,-2.569187l9.883835,0.80365c0,0 0,-3.763988 -1.253193,-4.929501c-0.91,-0.846428 -5.320366,-2.213829 -7.680691,-2.904591c0.631054,-4.954422 1.355366,-11.272388 1.865307,-17.655201l23.859238,4.85675c0.632927,-1.387089 1.143303,-3.476543 -0.427315,-5.299751c-1.165123,-1.352394 -15.495529,-7.349104 -22.825523,-10.358953c0.087616,-3.308828 0.055405,-6.40176 -0.150143,-9.052284l0,-0.00631c-0.20372,-2.622749 -0.576351,-4.812962 -1.180988,-6.372328c-0.30254,-0.780253 -0.663174,-1.405215 -1.103001,-1.841453c-0.440044,-0.436505 -0.961491,-0.677117 -1.547714,-0.677117l0,0z" fill-opacity="null" stroke-opacity="null" stroke-width="2" fill="#05111c" />
    </svg>
  </div>
!

CSS 

              
                body {
  margin: 0;
}

h1,
p {
  text-align: center;
}

.canvas {
  border: 1px solid #000;
  width: 580px;
  height: 400px;
  margin: auto;
}

/* https://bugs.chromium.org/p/chromium/issues/detail?id=637543*/
/*
  motion-offset -> offset-distance
  motion-path -> offset-path
  motion-rotation -> offset-rotation
  motion -> offset
*/
.path {
  motion-path: path('m232.771103, 329.79953c-102.829727, -78.900574 -139.598976, -128.812088 -139.897499, -189.912598c-0.270775, -55.699638 45.11657, -109.459106 92.15345, -109.14909c23.485428, 0.155491 73.868423, 20.65649 91.709885, 37.317997c8.990051, 8.395851 13.248871, 7.567986 33.261871, -6.467178c54.464142, -38.195642 107.654175, -38.997543 142.101776, -2.141006c55.054443, 58.903046 45.031464, 129.243813 -28.812988, 202.207039c-39.259857, 38.791107 -124.994751, 107.608795 -134.060852, 107.608795c-2.761017, 0 -28.16275, -17.759216 -56.455643, -39.463959l0, 0z');
  offset-path: path('m232.771103, 329.79953c-102.829727, -78.900574 -139.598976, -128.812088 -139.897499, -189.912598c-0.270775, -55.699638 45.11657, -109.459106 92.15345, -109.14909c23.485428, 0.155491 73.868423, 20.65649 91.709885, 37.317997c8.990051, 8.395851 13.248871, 7.567986 33.261871, -6.467178c54.464142, -38.195642 107.654175, -38.997543 142.101776, -2.141006c55.054443, 58.903046 45.031464, 129.243813 -28.812988, 202.207039c-39.259857, 38.791107 -124.994751, 107.608795 -134.060852, 107.608795c-2.761017, 0 -28.16275, -17.759216 -56.455643, -39.463959l0, 0z');
  animation: sweep 6s linear infinite;
}

.plane {
  transform: rotate(90deg) translateX(-62%);
}

.square {
  width: 0px;
  height: 0px;
  line-height: 0;
  position: absolute;
  background-color: rgba(63, 140, 50, 0.8);
  animation-name: reverse;
}

.square1:after {
  content: '';
  display: block;
  width: 70px;
  height: 30px;
  transform: translateY(-50%);
  background-color: rgba(63, 140, 50, 0.8);
}

.square2 {
  width: 70px;
  height: 30px;
  line-height: 30px;
  background-color: red;
}

@keyframes sweep {
  0% {
    motion-offset: 0;
    offset-distance: 0;
  }

  to {
    motion-offset: 100%;
    offset-distance: 100%;
  }
}

@keyframes reverse {
  0% {
    motion-offset: 0;
    offset-distance: 0;
  }

  to {
    motion-offset: -100%;
    offset-distance: -100%;
  }
}
!

JS
!
999px

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