Triangles $ABC$, $ADE$, and $EFG$ are all equilateral. Points $D$ and $G$ are midpoints of $\overline{AC}$ and $\overline{AE}$, respectively. If $AB = 4$, what is the perimeter of figure $ABCDEFG$?

$\text{(A)}\ 12\qquad\text{(B)}\ 13\qquad\text{(C)}\ 15\qquad\text{(D)}\ 18\qquad\text{(E)}\ 21$
The large triangle $ABC$ has sides of length $4$.  The medium triangle has sides of length $2$.  The small triangle has sides of length $1$.  There are $3$ segment sizes, and all segments depicted are one of these lengths.
Starting at $A$ and going clockwise, the perimeter is:
$AB + BC + CD + DE + EF + FG + GA$
$4 + 4 + 2 + 2 + 1 + 1 + 1$
$15$, thus the answer is $\boxed{C}$