Warning, /graphics/tikzkit/texamples/bezier.tex is written in an unsupported language. File is not indexed.

 \documentclass[a4paper,10pt]{article}
 \usepackage[utf8]{inputenc}
 \usepackage[pdftex,active,tightpage]{preview}
 \usepackage{tikz}
 \PreviewEnvironment{tikzpicture}
 
 \begin{document}
 \thispagestyle{empty}
 \begin{tikzpicture}
   \node[draw, circle, fill=yellow] (a) at (0, 0) {a};
   \node[draw, circle, fill=blue,minimum size=3cm] (b) at (2, 0) {a};
 
   \draw[thin] (a) to[bend left=90] (b);
   \draw[thin, green, dashed] (a.90) to[bend left=90] (b.90);
   \draw[thin, red, dotted] (a.north) to[bend left=90] (b.north);
 %   \draw[thin,red, dotted] (a.north) to[bend left=90] (b.north);
 %   \draw[thin,blue, dotted] (a.north) to[bend left=90] (b.center);
 
   \draw[rotate=135] (b.center) -- +(2, 0);
 
   % tikzlibrarytopaths.code.tex
   % looseness = 1 (default)
   % factor = 0.3915
 \end{tikzpicture}
 \end{document}