An architectural trefoil combined with an equilateral triangle (interlaced version). A traditional Christian Trinitarian symbol.
Vector version of File:Trefoil-Architectural-Equilateral-Triangle-interlaced.png, converted from the following PostScript source code:

%!
300 396 translate
.75 dup scale
18.22 setlinewidth
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33.40333 setlinewidth
/e{-344.5078 -198.90167 moveto 344.5078 -198.90167 lineto 0
397.80333 lineto closepath}def e 0 s stroke
15.18333 setlinewidth
e 1 s stroke
33.40333 setlinewidth
0 s -157.78983 91.1 198.90167 59 71 arc stroke 157.78983 91.1
198.90167 -61 -49 arc stroke 0 -182.2 198.90167 179 191 arc
stroke
15.18333 setlinewidth
1 s -157.78983 91.1 198.90167 58 72 arc stroke 157.78983 91.1
198.90167 -62 -48 arc stroke 0 -182.2 198.90167 178 192 arc
stroke showpage
%EOF
AnonMoos (first uploaded SVG file version by Saratogas)