Is it possible to add a linecap to only one end of a stroke? Not both ends as is the default shown in the sample below.
<?xml version="1.0"?>
<svg width="120" height="120" viewBox="0 0 120 120" version="1.1" xmlns="http://www.w3.org/2000/svg">
<line stroke-linecap="butt"
x1="30" y1="30" x2="30" y2="90"
stroke="teal" stroke-width="20"/>
<line stroke-linecap="round"
x1="60" y1="30" x2="60" y2="90"
stroke="teal" stroke-width="20"/>
<path d="M30,30 L30,90 M60,30 L60,90 M90,30 L90,90"
stroke="white" />
</svg>Another flexible solution using a single line and markers/marker-ends as suggested by Paulie_D:
<svg width="120" height="120" viewBox="0 0 120 120" version="1.1" xmlns="http://www.w3.org/2000/svg">
<defs>
<marker id="round" viewBox="-1 -1 2 2" markerWidth="1" orient="auto">
<circle r="1" fill="teal"/>
</marker>
</defs>
<line x1="30" y1="90" x2="30" y2="30"
stroke="teal" stroke-width="20" marker-end="url(#round)"/>
<line stroke-linecap="round"
x1="60" y1="30" x2="60" y2="90"
stroke="teal" stroke-width="20"/>
<line x1="90" y1="30" x2="90" y2="90"
stroke="teal" stroke-width="20" marker-end="url(#round)"/>
<path d="M30,30 L30,90 M60,30 L60,90 M90,30 L90,90"
stroke="white"/>
</svg>