ball bearing

ball.tex

\documentclass[tikz,border=0.3mm]{standalone}
\usepackage{tikz,ifthen}
\usepackage{contour}
\usepackage{arrayjob}

\begin{document}
\begin{tikzpicture}[scale=2.5, every node/.style={transform shape}, every draw/.style={transform shape}]

\definecolor{gray55} {HTML}{555555}
\definecolor{gray44} {HTML}{444444}
\definecolor{gray33} {HTML}{333333}
\definecolor{gray22} {HTML}{222222}
\definecolor{gray66} {HTML}{666666}
\definecolor{gray88} {HTML}{888888}
\definecolor{grayee} {HTML}{eeeeee}
\definecolor{graycc} {HTML}{cccccc}
\definecolor{graydd} {HTML}{dddddd}
\definecolor{grayff} {HTML}{ffffff}


\newarray\names
\readarray{names}{$+$&$-$&$\times$&$/$}

% modified from
% https://tex.stackexchange.com/questions/54193/how-to-draw-a-shaded-sphere
\makeatletter
\pgfdeclareradialshading[tikz@ball]{ball}{\pgfqpoint{-20bp}{20bp}}{%
 color(0bp)=(tikz@ball!0!white);
 color(9bp)=(tikz@ball!0!white);
 color(21bp)=(tikz@ball!55!black);
 color(25bp)=(black!30);
 color(30bp)=(black!20)}
\makeatother

\def\shinyballs{1}
\def\nBalls{7}

\def\rradius{0.015}
\def\raceOuter{3*0.28}
\def\raceInner{1.75*0.28}
\def\raceOuterb{3.25*0.28}
\def\raceInnerb{1.5*0.28}


\def\nGuides{7}

% background
\fill [gray44,even odd rule] (0,0) circle[radius=\raceInner] circle[radius=\raceOuter];
\foreach \i in {1,...,\nGuides} {
    \draw [gray33] (0,0) circle ({\raceInner + (\raceOuter - \raceInner) * (\i / (\nGuides+1))});
}

% Draw the balls, equally spaced
\foreach \i in {1,...,\nBalls} {

\ifthenelse{\shinyballs = 1}{
    % shaded balls
        \shade [ball color=white] ({(\raceInner + \raceOuter)/2 * cos(360*\i/\nBalls)}, {(\raceInner + \raceOuter)/2 * sin(360*\i/\nBalls)}) circle (0.625*0.256);
        \fill[even odd rule,shading = axis,rectangle, left color=gray66, right color=gray88, shading angle=225, anchor=north]
            ({(\raceInner + \raceOuter)/2 * cos(360*\i/\nBalls)}, {(\raceInner + \raceOuter)/2 * sin(360*\i/\nBalls)}) circle[radius=0.15] circle[radius=0.16];
}{
    % flat balls
        \fill[even odd rule,shading = axis,rectangle, left color=grayee, right color=grayff, shading angle=225, anchor=north]
            ({(\raceInner + \raceOuter)/2 * cos(360*\i/\nBalls)}, {(\raceInner + \raceOuter)/2 * sin(360*\i/\nBalls)}) circle (0.625*0.25);
        \fill[even odd rule,shading = axis,rectangle, left color=gray88, right color=grayee, shading angle=225, anchor=north]
            ({(\raceInner + \raceOuter)/2 * cos(360*\i/\nBalls)}, {(\raceInner + \raceOuter)/2 * sin(360*\i/\nBalls)}) circle[radius=0.15] circle[radius=0.16];
}
}

% races
\fill [lightgray,even odd rule,shading = axis,rectangle, left color=graycc, right color=grayff, shading angle=225, anchor=north] (0,0) circle[radius=\raceInner] circle[radius=\raceInnerb];
\fill [lightgray,even odd rule,shading = axis,rectangle, left color=graycc, right color=grayff, shading angle=225, anchor=north] (0,0) circle[radius=\raceOuter] circle[radius=\raceOuterb];
\fill [lightgray,even odd rule,shading = axis,rectangle, left color=grayee, right color=gray88, shading angle=225, anchor=north] (0,0) circle[radius={\raceInnerb-\rradius}] circle[radius=\raceInnerb];
\fill [lightgray,even odd rule,shading = axis,rectangle, left color=gray88, right color=grayee, shading angle=225, anchor=north] (0,0) circle[radius={\raceInner+\rradius}] circle[radius=\raceInner];
\fill [lightgray,even odd rule,shading = axis,rectangle, left color=grayee, right color=gray88, shading angle=225, anchor=north] (0,0) circle[radius={\raceOuter-\rradius}] circle[radius=\raceOuter];
\fill [lightgray,even odd rule,shading = axis,rectangle, left color=gray88, right color=grayee, shading angle=225, anchor=north] (0,0) circle[radius={\raceOuterb+\rradius}] circle[radius=\raceOuterb];

\draw ({(\raceInner + \raceOuter)/2 * cos(360*0/\nBalls)}, {(\raceInner + \raceOuter)/2 * sin(360*0/\nBalls)}) node {\tiny \contour{graycc}{$+$}};
\draw ({(\raceInner + \raceOuter)/2 * cos(360*1/\nBalls)}, {(\raceInner + \raceOuter)/2 * sin(360*1/\nBalls)}) node {\tiny \contour{graycc}{$-$}};
\draw ({(\raceInner + \raceOuter)/2 * cos(360*2/\nBalls)}, {(\raceInner + \raceOuter)/2 * sin(360*2/\nBalls)}) node {\tiny \contour{graycc}{$\times$}};
\draw ({(\raceInner + \raceOuter)/2 * cos(360*3/\nBalls)}, {(\raceInner + \raceOuter)/2 * sin(360*3/\nBalls)}) node {\tiny \contour{graycc}{$/$}};
\draw ({(\raceInner + \raceOuter)/2 * cos(360*4/\nBalls)}, {(\raceInner + \raceOuter)/2 * sin(360*4/\nBalls)}) node[scale=0.9] {\tiny \contour{graycc}{$\!\sqrt{}$}};
\ifthenelse{\nBalls > 5}{\draw ({(\raceInner + \raceOuter)/2 * cos(360*5/\nBalls)}, {(\raceInner + \raceOuter)/2 * sin(360*5/\nBalls)}) node[scale=0.9] {\tiny \contour{graycc}{$\pi$}}}{};
\ifthenelse{\nBalls > 6}{\draw ({(\raceInner + \raceOuter)/2 * cos(360*6/\nBalls)}, {(\raceInner + \raceOuter)/2 * sin(360*6/\nBalls)}) node[scale=0.9] {\tiny \contour{graycc}{$\zeta$}}}{};

\contourlength{0.12mm}
\draw[color=black] (0,-1.30) node[] {\LARGE \contour{grayee}{\textbf{FLINT}}};
%\draw[color=black] (0,-1.30) node[] {\LARGE \textbf{FLINT}};
\draw[color=black] (0,-1.65) node[scale=0.8] {\tiny \textit{Fast Library for Number Theory}};


\end{tikzpicture}
\end{document}