console
<!-- <svg width="400" height="400">
<defs>
<mask id="test-mask">
<rect x="5" y="5" width="390" height="390" fill="white">
</rect>
<text x="10" y="20" style="fill:#0000ff;stroke:black">SVG Text Example</text>
</mask>
</defs>
<rect x="5" y="5" width="390" height="390" fill="red" mask="url(#test-mask)"></rect>
</svg> -->
<svg width="400" height="400">
<defs>
<path
id="p"
d="M5 5 L395 5 L395 395 L5 395 Z"
fill="none"></path>
<mask id="fly-mask">
<circle r="50" cx="0" cy="0" fill="white">
<animateMotion
path="M5 5 L395 5 L395 395 L5 395 Z"
dur="2s"
repeatCount="indefinite" />
</circle>
</mask>
<linearGradient id="fly-gradient">
<stop offset="0%" stop-color="red" stop-opacity="0.5"></stop>
<stop offset="50%" stop-color="pink"></stop>
<stop offset="100%" stop-color="yellow"></stop>
</linearGradient>
<radialGradient
id="fly-radia"
cx="50%"
cy="50%"
fx="50%"
fy="50%"
r="50%"
>
<stop offset="0%" stop-color="#fff" stop-opacity="1"></stop>
<stop offset="100%" stop-color="#fff" stop-opacity="0"></stop>
</radialGradient>
</defs>
<use href="#p" stroke-width="3" stroke="#d77"></use>
<use href="#p" stroke-width="3" stroke="#4fd2dd" mask="url(#fly-mask)"></use>
</svg>