I'm trying to draw this plot
,
I've done the triangle, but I'm not able to draw the curves between $A_1$ to $A_2$, between $A_3$ to $B_3$ etc.
\begin{tikzpicture} \path[draw, line width=1.5pt](7,7)--(7,0)--(3,3.5)--cycle; \draw[blue, thick] (7, 5) .. controls (5.5,5.8) .. (6, 6.1); \end{tikzpicture} Can anyone give some suggestions, on how to do it?
\documentclass[border=5mm]{standalone} \usepackage{tikz} \usetikzlibrary{calc} \begin{document} \begin{tikzpicture} \path (7,7) coordinate (A) (7,0) coordinate (B) (3,3.5) coordinate (C) ($(A)!0.25!(B)$) coordinate (A1) node[right] {$A_1$} ($(A)!0.3!(C)$) coordinate (A2) node[above left] {$A_2$} ($(A)!0.6!(C)$) coordinate (A3) node[above left] {$A_3$} ($(B)!0.25!(A)$) coordinate (B1) node[right] {$B_1$} ($(B)!0.3!(C)$) coordinate (B2) node[below left] {$B_2$} ($(B)!0.6!(C)$) coordinate (B3) node[below left] {$B_3$}; \draw[blue,thick] (A1) to[bend left=20] (A2) (A1) to[bend left=20] (A3) (B1) to[bend right=20] (B2) (B1) to[bend right=20] (B3); \draw[red,thick] (A2) to[bend right=30] (B2) (A3) to[bend left=10] (B3); \draw[line width=1.5pt] (A) -- (B) -- (C) -- cycle; \end{tikzpicture} \end{document} 
Instead of controls, I use in/out angles specifications.
\documentclass[12pt]{article} \usepackage{tikz} \usepackage{xcolor} \begin{document} \begin{tikzpicture} \path[draw, line width=1.5pt](7,7)--(7,0) node [pos=.3,label={0:$A_1$}] (A1) {} node [pos=.6,label={0:$B_1$}] (B1) {} -- (3,3.5) node [pos=.4,label={[anchor=north east]0:$B_2$}] (B2) {} node [pos=.7,label={[anchor=north east]0:$B_3$}] (B3) {}--cycle node [pos=.3,label={[anchor=south east]0:$A_3$}] (A3) {} node [pos=.6,label={[anchor=south east]0:$A_2$}] (A2) {}; \draw [blue, thick] (A1.center) to [out=170, in=-30] (A2.center); \draw [blue, thick] (A1.center) to [out=190, in=-20] (A3.center); \draw [red, thick] (A2.center) to [out=-100, in=100] (B2.center); \draw [red, thick] (A3.center) to [out=-80, in=80] (B3.center); \draw [blue, thick] (B1.center) to [out=170, in=30] (B2.center); \draw [blue, thick] (B1.center) to [out=170, in=20] (B3.center); \end{tikzpicture} \end{document} 
Purely for comparison, here is a Metapost version.
\documentclass[border=5mm]{standalone} \usepackage{luamplib} \begin{document} \mplibtextextlabel{enable} \begin{mplibcode} beginfig(1); path triangle; triangle = origin -- 100 up -- 100 left -- 100 down -- cycle; pair A[], B[]; A1 = point 0.42 of triangle; A2 = point 1.4 of triangle; A3 = point 1.6 of triangle; B1 = point -0.42 of triangle; B2 = point -1.4 of triangle; B3 = point -1.6 of triangle; def connector(expr a, b, r) = a {(b-a) rotated r} .. b enddef; draw connector(A1, A2, +14) withcolor 2/3 blue; draw connector(A1, A3, +16) withcolor 2/3 blue; draw connector(B1, B2, -14) withcolor 2/3 blue; draw connector(B1, B3, -16) withcolor 2/3 blue; draw connector(A2, B2, -12) withcolor 3/4 red; draw connector(A3, B3, +12) withcolor 3/4 red; draw triangle withpen pencircle scaled 3/4; forsuffixes @ = A, B: label.rt("$" & str @ & "_1$", @1); endfor for i=2, 3: label.ulft("$A_" & decimal i & "$", A[i]); label.llft("$B_" & decimal i & "$", B[i]); endfor endfig; \end{mplibcode} \end{document} Compile this with lualatex to get a PDF that looks like this:
\documentclass[border=5mm]{standalone} \usepackage{tikz} \usetikzlibrary{angles,quotes,calc} \usepackage{siunitx} \begin{document} \begin{tikzpicture}[ my angle1/.style = {draw,thick,red, %,fill=teal!30, angle radius=24mm, angle eccentricity=1.1, right, inner sep=1pt, font=\small} ] \draw[thick] (6,0) coordinate[%label=below:$A$ ](a) --(0,5) coordinate[%label=below:$C$ ](c) --(6,10) coordinate[%label=above:$B$ ](b) -- cycle; \path (6,10) coordinate (A) (6,0) coordinate (B) (0,5) coordinate (C) ($(A)!0.25!(B)$) coordinate (A1) node[right] {$A_1$} ($(A)!0.3!(C)$) coordinate (A2) node[above left] {$A_2$} ($(A)!0.6!(C)$) coordinate (A3) node[above left] {$A_3$} ($(B)!0.25!(A)$) coordinate (B1) node[right] {$B_1$} ($(B)!0.3!(C)$) coordinate (B2) node[below left] {$B_2$} ($(B)!0.6!(C)$) coordinate (B3) node[below left] {$B_3$}; \draw[thick,red] (2.325,6.9) arc (235:327:2.6); \draw[thick,red] (6.0,2.4) arc (30:127:2.6); \draw[thick,blue] (2.15,3.2) arc (330:385:4); \draw[thick,blue] (4.2,8.5) arc (150:210:7); \pic[my angle1] {angle = c--b--a}; \pic[my angle1] {angle = b--a--c}; \end{tikzpicture} \end{document} 
