Creating Donut chart

Question

I have seen a donut chart, but it does not look like a ring, rather the portions of the ring are disjoint.

2D version

3D version

How to create them?

Related Questions: 1. How to design a 3D donut pie chart with pgf-plot? 2. How can I produce a 'ring (or wheel) chart' like that on page 88 of the PGF manual? 3. How to draw a coffee cup (thanks to @PrzemysławScherwentke) 4. Create a ring diagram in TeX

For the 2D part, I tried to do some tweak on the following code, which is shamelessly copied from the answer of the 4th question, but found no such obvious way:

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows}
\begin{document}

% Adjusts the size of the wheel:
\def\innerradius{1.8cm}
\def\outerradius{2.2cm}

% The main macro
\newcommand{\wheelchart}[1]{
    % Calculate total
    \pgfmathsetmacro{\totalnum}{0}
    \foreach \value/\colour/\name in {#1} {
        \pgfmathparse{\value+\totalnum}
        \global\let\totalnum=\pgfmathresult
    }

    \begin{tikzpicture}

      % Calculate the thickness and the middle line of the wheel
      \pgfmathsetmacro{\wheelwidth}{\outerradius-\innerradius}
      \pgfmathsetmacro{\midradius}{(\outerradius+\innerradius)/2}

      % Rotate so we start from the top
      \begin{scope}[rotate=90]

      % Loop through each value set. \cumnum keeps track of where we are in the wheel
      \pgfmathsetmacro{\cumnum}{0}
      \foreach \value/\colour in {#1} {
            \pgfmathsetmacro{\newcumnum}{\cumnum + \value/\totalnum*360}

            % Calculate the percent value
            \pgfmathsetmacro{\percentage}{\value/\totalnum*100}
            % Calculate the mid angle of the colour segments to place the labels
            \pgfmathsetmacro{\midangle}{-(\cumnum+\newcumnum)/2}

            % This is necessary for the labels to align nicely
            \pgfmathparse{
               (-\midangle<180?"west":"east")
            } \edef\textanchor{\pgfmathresult}
            \pgfmathsetmacro\labelshiftdir{1-1*(-\midangle>180)}

            % Draw the color segments. Somehow, the \midrow units got lost, so we add 'pt' at the end. Not nice...
            \fill[\colour] (-\cumnum:\outerradius) arc (-\cumnum:-(\newcumnum):\outerradius) --
            (-\newcumnum:\innerradius) arc (-\newcumnum:-(\cumnum):\innerradius) -- cycle;

            % Set the old cumulated angle to the new value
            \global\let\cumnum=\newcumnum
        }

      \end{scope}
    \end{tikzpicture}
}
\wheelchart{26/cyan,  28/orange, 33.5/yellow, 12/blue!50!red}

\end{document}