You can also see how five copies of the McWorter pentigree fit together by successively adding copies using the buttons below.
The scaling factor is still r = 0.381966. This leads to the following IFS [Details]:
\({f_1}({\bf{x}}) = \left[ {\begin{array}{*{20}{c}}
{0.309} & {  0.255} \\
{0.255} & {0.309} \\
\end{array}} \right]{\bf{x}}\)

scale by r, rotate by 36° 
\({f_2}({\bf{x}}) = \left[ {\begin{array}{*{20}{c}}
{0.309} & {  0.254} \\
{0.254} & {0.309} \\
\end{array}} \right]{\bf{x}} + \left[ {\begin{array}{*{20}{c}}
{0.727} \\
{0} \\
\end{array}} \right]\)

scale by r, rotate by 36° 
\({f_3}({\bf{x}}) = \left[ {\begin{array}{*{20}{c}}
{0.309} & {  0.255} \\
{0.255} & {0.309} \\
\end{array}} \right]{\bf{x}} + \left[ {\begin{array}{*{20}{c}}
{0.225} \\
{0.691} \\
\end{array}} \right]\)

scale by r, rotate by 36° 
\({f_4}({\bf{x}}) = \left[ {\begin{array}{*{20}{c}}
{0.309} & {  0.255} \\
{0.255} & {0.309} \\
\end{array}} \right]{\bf{x}} + \left[ {\begin{array}{*{20}{c}}
{0.588} \\
{0.427} \\
\end{array}} \right]\)

scale by r, rotate by 36° 
\({f_5}({\bf{x}}) = \left[ {\begin{array}{*{20}{c}}
{0.309} & {  0.255} \\
{0.255} & {0.309} \\
\end{array}} \right]{\bf{x}} + \left[ {\begin{array}{*{20}{c}}
{0.588} \\
{0.427} \\
\end{array}} \right]\)

scale by r, rotate by 36° 
\({f_6}({\bf{x}}) = \left[ {\begin{array}{*{20}{c}}
{0.309} & {  0.255} \\
{0.255} & {0.309} \\
\end{array}} \right]{\bf{x}} + \left[ {\begin{array}{*{20}{c}}
{0.225} \\
{ 0.691} \\
\end{array}} \right]\)

scale by r, rotate by 36° 
\[\sum\limits_{k = 1}^6 {{r^d}} = 1 \quad \Rightarrow \quad d = \frac{{\log (1/6)}}{{\log (r )}} = 1.86172\]