You can find the plugin at https://sites.google.com/site/spirixcode/
In order to create the shape you want, you will need to create two templates … one for the triangle and one for the circle. If the circle is made up of 24 segments, then each of the edges of the triangle should be 8 segments (1/3 of 24). The Spirix Create Group function will grab all un-grouped geometry in the model in the order they were created. To construct the first template, create the triangle and group it the normal way. Then trace around the triangle starting at the right-hand point and continuing counter-clockwise around the perimeter. After creating each edge, you need to divide it before moving on to creating the next line. When done, use the Spirix Create Group and give it a name:
For the circle, simply create a circle with 24 segments picking a radius point on the x-axis (this aligns the start and end of the circle with the start and end of the triangle). Use the Spirix Create Group to create a second group with a different name:
Noting that the center-to-apex distance of the triangle is (arbitrarily) about 48 inches, I used a height of 48 inches with the following Spirix parameters:
You can use the move, scale, rotate, and mirror tools to modify the templates … however, editing them inside the group will usually change the order of the edges and cause unexpected results.