<!DOCTYPE html>
<svg>
<filter id="dilate">
<feMorphology operator="dilate" radius="-1"/>
</filter>
<rect width="100" height="100" fill="green" filter="url(#dilate)"/>
<filter id="erode">
<feMorphology operator="erode" radius="-1"/>
</filter>
<rect width="100" height="100" fill="green" filter="url(#erode)" x="100"/>
</svg>