# How to draw the “sri-cakra” (sri-yantra") using Tikz?

I want to draw the "sricakra" (also know as "srityantra") using Tikz, as shown in the following link: https://codegolf.stackexchange.com/questions/42410/draw-sri-yantra

How does one draw the sixteen and eight petal lotus arranges in circular form in this diagram?

Here is a detailed description of the construction. https://web.archive.org/web/20130807162656/http://www.saralhindi.com/Shri_Yantra/makingsky14steps_eng.htm

## 1 Answer

You can start with this. I've more o less followed steps from How to draw Shri Yantra in 14 steps

\documentclass[tikz,border=2mm]{standalone}

\usetikzlibrary{positioning, shapes.geometric, intersections,calc, backgrounds}

\begin{document}

\pgfdeclarelayer{minus1}
\pgfdeclarelayer{minus2}
\pgfdeclarelayer{minus3}
\pgfsetlayers{minus3,minus2,minus1,background,main}

\begin{tikzpicture}

%step-1
\draw[name path=circ, thick, fill=red!30] (0,0) circle (2.5cm);
\node[regular polygon, regular polygon sides=12, minimum size=5cm, shape border rotate=15] (p) {};

%\node [above] at (p.corner 1) {1};
%\node [above left] at (p.corner 2) {2};
\coordinate (1a) at (p.corner 7);

\path[name path=1--4] (p.corner 1)--(p.corner 4);
\path[name path=1--10] (p.corner 1)--(p.corner 10);
\path[name path=7--11] (p.corner 7)--(p.corner 11);
\path[name path=7--3] (p.corner 7)--(p.corner 3);

\path[name intersections={of=1--4 and 7--3, by=aux1}];
\path[name intersections={of=1--10 and 7--11, by=aux2}];

\path[name path=aux1--aux2] ([xshift=-2cm]aux1)--([xshift=2cm]aux2);

\path[name intersections={of=aux1--aux2 and circ, by={1b,1c}}];

\draw[thick, name path=tri1](1a)--(1b)-- coordinate[midway](5a) (1c)--cycle;

%step-2
\coordinate (2a) at (p.corner 1);

\path[name path=1--9] (p.corner 1)--(p.corner 9);
\path[name path=1--5] (p.corner 1)--(p.corner 5);
\path[name path=7--10] (p.corner 7)--(p.corner 10);
\path[name path=7--4] (p.corner 7)--(p.corner 4);

\path[name intersections={of=1--5 and 7--4, by=aux1}];
\path[name intersections={of=1--9 and 7--10, by=aux2}];

\path[name path=aux1--aux2] ([xshift=-2cm]aux1)--([xshift=2cm]aux2);

\path[name intersections={of=aux1--aux2 and circ, by={2b,2c}}];

\draw[thick, name path=tri2](2a)--(2b)--coordinate[midway](9a) (2c)--cycle;

%steps-3 and 4

\coordinate (S1) at (135:2.5cm);
\coordinate (S2) at (45:2.5cm);
\coordinate (S3) at (-45:2.5cm);
\coordinate (S4) at (-135:2.5cm);

\path[name path=rect] (S1)-- coordinate[midway](4a) (S2) -- (S3)--coordinate[midway](3a) (S4)--cycle;

\path [name intersections={of=tri1 and tri2, by={*4,x,*1,*2,x,*3}}];

\path [name path=3a--*1] (3a)--($(3a)!1.5!(*1)$);
\path [name intersections={of=rect and 3a--*1, by={x,3b}}];

\path [name path=3a--*2] (3a)--($(3a)!1.5!(*2)$);
\path [name intersections={of=rect and 3a--*2, by={3c}}];

\draw[name path=tri3,thick] (3a)--(3b)--coordinate[midway](6a) (3c)--cycle;

\path [name path=4a--*3] (4a)--($(4a)!1.5!(*3)$);
\path [name intersections={of=rect and 4a--*3, by={x,4b}}];

\path [name path=4a--*4] (4a)--($(4a)!1.5!(*4)$);
\path [name intersections={of=rect and 4a--*4, by={x,4c}}];

\draw[name path=tri4,thick] (4a)--(4b)--coordinate[midway](8a)(4c)--cycle;

%Step-5
\path [name intersections={of=tri3 and tri2, by={x,*5,x,x,*6,x}}];

\path [name intersections={of=tri1 and tri4, by={*8,x,x,x,x,*7}}];

\path [name path=5a--*7] (5a)--($(5a)!1.5!(*7)$);
\path [name intersections={of=rect and 5a--*7, by=5b}];

\path [name path=5a--*8] (5a)--($(5a)!1.5!(*8)$);
\path [name intersections={of=rect and 5a--*8, by=5c}];

\draw[name path=tri5,thick] (5a)--(5b)--(5c)--cycle;

%%Step-6
\path [name path=*1--*4] (*1)--(*4);
\path [name path=*2--*3] (*2)--(*3);

\path  [name intersections={of=tri3 and *1--*4, by=6c}];
\path  [name intersections={of=tri3 and *2--*3, by={6b,x}}];

\draw[name path=tri6,thick] (6a)--(6b)-- coordinate[midway](7a) (6c)--cycle;

%Step-7

\path [name intersections={of=tri2 and tri3, by={x,*1,x,x,*3,x}}];
\path [name intersections={of=tri1 and tri4, by={x,x,*2,*4,x,x}}];

\path [name path=*1--*2] (7a)--($(7a)!1.5!(*1)$);
\path [name intersections={of=rect and *1--*2, by=7b}];

\path [name path=*3--*4] (7a)--($(7a)!1.5!(*3)$);
\path [name intersections={of=rect and *3--*4, by=7c}];

\draw[name path=tri7,thick] (7a)--(7b)-- (7c)--cycle;

%Step-8

\path [name intersections={of=tri6 and tri7, by={*1,x,*2}}];
\path [name path=*1--*2] ($(*2)!1.5!(*1)$)--($(*1)!1.5!(*2)$);
\path [name intersections={of=tri4 and *1--*2, by={8b,8c}}];

\draw[name path=tri8,thick] (8a)--(8b)-- (8c)--cycle;

%Step-9

\path [name intersections={of=tri5 and tri7, by={*1,*2}}];
\path [name path=*1--*2] ($(*2)!2.5!(*1)$)--($(*1)!2.5!(*2)$);
\path [name intersections={of=tri6 and *1--*2, by={9b,9c}}];

\draw[name path=tri9,thick] (9a)--(9b)-- (9c)--cycle;

\fill[blue!30, even odd rule] (1a)--(1b)--(1c)--cycle (2a)--(2b)--(2c)--cycle (3a)--(3b)--(3c)--cycle (4a)--(4b)--(4c)--cycle (5a)--(5b)--(5c)--cycle (6a)--(6b)--(6c)--cycle (7a)--(7b)--(7c)--cycle (8a)--(8b)--(8c)--cycle (9a)--(9b)--(9c)--cycle;

%Step-10

\draw[fill=red!30] (barycentric cs:*1=1,*2=1,9a=1) circle (2pt);

%Step-11

\begin{scope}[on background layer]
\draw [fill=green] circle (3cm);

\foreach \i [evaluate=\i as \start using 22.5+45*\i] in {0,...,7}
\draw[fill=blue!30] (\start:2.5) to[out=10, in=170, relative] ({\start-22.5}:3) to [out=10, in=170, relative] ({\start-45}:2.5) arc [start angle={\start-45}, delta angle=45, radius=2.5cm]--cycle;
\end{scope}

%Step-12

\begin{pgfonlayer}{minus1}
\draw [fill=red] circle (3.5cm);

\foreach \i [evaluate=\i as \start using 11.25+22.5*\i] in {0,...,15}
\draw[fill=blue!30] (\start:3) to[out=10, in=170, relative] ({\start-11.25}:3.5) to [out=10, in=170, relative] ({\start-22.5}:3) arc [start angle={\start-11.25}, delta angle=22.5, radius=3.5cm]--cycle;
\end{pgfonlayer}

%Step-13

\begin{pgfonlayer}{minus2}
\draw [fill=blue!39] circle (4cm);
\draw [line width=2mm, blue!70!black] circle (3.75cm);
\end{pgfonlayer}

%Step-14

\begin{pgfonlayer}{minus3}
\node [fill=yellow, minimum size=8.25cm] (b) {};
\node [fill=yellow, minimum width=9.5cm, minimum height=3cm] (bh) {};
\node [fill=yellow, minimum height=9.5cm, minimum width=3cm] (bv) {};
\node [fill=yellow, minimum height=8mm, minimum width=6cm] at (bv.north) (bn) {};
\node [fill=yellow, minimum height=8mm, minimum width=6cm] at (bv.south) (bs) {};
\node [fill=yellow, minimum width=8mm, minimum height=6cm] at (bh.west) (bw) {};
\node [fill=yellow, minimum width=8mm, minimum height=6cm] at (bh.east) (be) {};
\draw [brown!60!black,line width=1mm]%
(be.south west)-|(be.north east)-|(bh.north-|be.west)-|(b.north east)-|(bv.east|-bn.south)-|(bn.north east)-|(bn.south west)-|(b.north-|bv.west)-|(b.west|-bh.north)-|(bw.north east)-|(bw.south west)-|(bw.east|-bh.south)-|(b.south west)-|(bv.west|-bs.north)-|(bs.south west)-|(bs.north east)-|(bv.east|-b.south)-|(b.east|-bh.south)-|cycle;

\end{pgfonlayer}

\end{tikzpicture}

\end{document} Update:

After testing this code on overleaf I've found that the behavior is not the same as on my computer. There step-8 command should be

\path [name intersections={of=tri6 and tri7, by={*1,x,x,*2}}];


because it finds four intersection points (instead of three) between triangles 6 and 7. In fact the whole picture in both systems show defects due to rounding errors.

For more curved petals you can change foreach commands in steps 11 and 12 to:

step-11

\foreach \i [evaluate=\i as \start using 22.5+45*\i] in {0,...,7}
\draw[fill=blue!30] (\start:2.5) .. controls ({\start-5}:2.85)
and ({\start-17.5}:2.75) .. ({\start-22.5}:3) ..
controls ({\start-27.5}:2.75) and ({\start-40}:2.85) ..
({\start-45}:2.5) arc [start angle={\start-45},
delta angle=45, radius=2.5cm]--cycle;


and

step 12

\foreach \i [evaluate=\i as \start using 11.25+22.5*\i] in {0,...,15}
\draw[fill=blue!30] (\start:3)  .. controls ({\start-2.5}:3.35)
and ({\start-8.75}:3.25) .. ({\start-11.25}:3.5) ..
controls ({\start-13.75}:3.25) and  ({\start-20}:3.35)..
({\start-22.5}:3) arc [start angle={\start-11.25},
delta angle=22.5, radius=3.5cm]--cycle;


These changes and some little changes in sizes of background rectangles (step-14) give us • Thanks. When I process the .tex source code posted here, with pdfLaTeX, the two innermost triangles do not align properly, and one line protrudes and does not form part of the triangle. . Also, it would be nice to make the rose petals in the diagram a little more curved. – Narayanaswami Oct 10 '15 at 9:51
• @Narayanaswami I've updated my answer. Probably the problem with step 8 is due to different tikz versions. I've shared a link to an Overleaf version which works. Petals are more curved now. – Ignasi Oct 12 '15 at 10:07
• could you kindly post the .tex file that gave the last version of the diagram (Oct 12)? – Narayanaswami Oct 26 '15 at 16:24
• After making the changes suggested by you, and then processing, I still get some lines in the innermost triangles not aligning properly, and the lotus petals are not curved. Hence, I request you post the complete .texx code that generated the last shown diagram. I am using TexLive 2014 in Ubuntu Linux. – Narayanaswami Oct 26 '15 at 16:27
• @Narayanaswami: the link on Overleaf is: overleaf.com/3429844cfckry. Probably TeXLive 2014 on Ubuntu uses an old TikZ version. You should consider updating your system. – Ignasi Oct 26 '15 at 16:43