<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" >
<style type="text/css" >
<![CDATA[
circle {
    stroke: blue;
    stroke-width: 5;
    fill: yellow;
}
]]>
</style>
<defs>
<filter id="drop-shadow-1">
    <feDropShadow flood-color="green"/>
</filter>
<filter id="drop-shadow-2">
    <feDropShadow stdDeviation="0" dx="0" dy="0" flood-color="green"/>
</filter>
<filter id="drop-shadow-3">
    <feDropShadow stdDeviation="0 10" dx="5" dy="5" flood-color="green"/>
</filter>
<filter id="drop-shadow-4">
    <feDropShadow stdDeviation="10 0" dx="5" dy="5" flood-color="green"/>
</filter>
<filter id="drop-shadow-5">
    <feDropShadow stdDeviation="10" dx="5" dy="5" flood-color="green"/>
</filter>
<filter id="drop-shadow-6">
    <feDropShadow stdDeviation="10" dx="-5" dy="-5" flood-color="green"/>
</filter>
<filter id="drop-shadow-7">
    <feDropShadow stdDeviation="128" dx="0" dy="0" flood-color="green"/>
</filter>
<filter id="drop-shadow-8">
    <feDropShadow stdDeviation="10" dx="5" dy="5" flood-opacity="0.5" flood-color="green"/>
</filter>
</defs>
<circle cx="75" cy="75" r="70" filter="url(#drop-shadow-1)" />
<circle cx="250" cy="75" r="70" filter="url(#drop-shadow-2)" />
<circle cx="425" cy="75" r="70" filter="url(#drop-shadow-3)" />
<circle cx="600" cy="75" r="70" filter="url(#drop-shadow-4)" />
<circle cx="75" cy="250" r="70" filter="url(#drop-shadow-5)" />
<circle cx="250" cy="250" r="70" filter="url(#drop-shadow-6)" />
<circle cx="425" cy="250" r="70" filter="url(#drop-shadow-7)" />
<circle cx="600" cy="250" r="70" filter="url(#drop-shadow-8)" />
</svg>