%% Visual review of the simplified surface anchors. Every marked percentage
%% is produced by show anchors; coincident boundary endpoints share a marker.
\documentclass{article}
\usepackage[paperwidth=21cm,paperheight=12cm,margin=8mm]{geometry}
\usepackage{tikzphysics}
\pagestyle{empty}

\newcommand{\anchorpage}[4]{%
  \noindent\textbf{#1}\quad\small 0 = start, 50 = midpoint, 100 = end\par\smallskip
  \begin{center}\begin{tikzpicture}
    \node[#2,show anchors,
      physics debug/anchor list={#3},
      physics debug/anchor families={#4},
      physics debug/anchor samples={0,50,100}] (S) {};
  \end{tikzpicture}\end{center}
  \clearpage
}

\begin{document}
\anchorpage{Ground}{ground,ground width=7cm,ground depth=1cm}%
  {surface,top-left,top-right,bottom-left,bottom-right}%
  {surface,bottom,left,right}
\anchorpage{Ceiling}{ceiling,ceiling width=7cm,ceiling depth=1cm}%
  {surface,top-left,top-right,bottom-left,bottom-right}%
  {surface,top,left,right}
\anchorpage{Wall left}{wall-left,wall height=4cm,wall thickness=1cm}%
  {surface,top-left,top-right,bottom-left,bottom-right}%
  {surface,top,bottom,left}
\anchorpage{Wall right}{wall-right,wall height=4cm,wall thickness=1cm}%
  {surface,top-left,top-right,bottom-left,bottom-right}%
  {surface,top,bottom,right}
\anchorpage{Platform left: floor}{platform-left,platform width=7cm,platform depth=2.5cm,
  strip width=0.6cm,wall angle=-135,wall inset=0.7cm,wall drop=0.5cm,
  physics debug/anchor legend yshift=-1.8cm}%
  {surface,pulley-center,floor-center}%
  {surface,bottom,left,right}
\anchorpage{Platform left: wall}{platform-left,platform width=7cm,platform depth=2.5cm,
  strip width=0.6cm,wall angle=-135,wall inset=0.7cm,wall drop=0.5cm}%
  {pulley-center,wall-root,wall-center}%
  {transition,wall-surface,wall-back,wall-base,wall-tip}
\anchorpage{Platform right: floor}{platform-right,platform width=7cm,platform depth=2.5cm,
  strip width=0.6cm,wall angle=-45,wall inset=0.7cm,wall drop=0.5cm,
  physics debug/anchor legend yshift=-1.8cm}%
  {surface,pulley-center,floor-center}%
  {surface,bottom,left,right}
\anchorpage{Platform right: wall}{platform-right,platform width=7cm,platform depth=2.5cm,
  strip width=0.6cm,wall angle=-45,wall inset=0.7cm,wall drop=0.5cm}%
  {pulley-center,wall-root,wall-center}%
  {transition,wall-surface,wall-back,wall-base,wall-tip}
\anchorpage{Platform both: floor}%
  {platform,platform width=7cm,platform depth=2.5cm,strip width=0.6cm,
   left wall angle=-135,right wall angle=-45,
   left wall inset=0.7cm,right wall inset=0.7cm,
   left wall drop=0.5cm,right wall drop=0.5cm,
   physics debug/anchor legend yshift=-1.8cm}%
  {surface,left-pulley-center,right-pulley-center,floor-center}%
  {surface,bottom,left,right}
\anchorpage{Platform both: left wall}%
  {platform,platform width=7cm,platform depth=2.5cm,strip width=0.6cm,
   left wall angle=-135,right wall angle=-45,
   left wall inset=0.7cm,right wall inset=0.7cm,
   left wall drop=0.5cm,right wall drop=0.5cm}%
  {left-pulley-center,left-wall-root,left-wall-center}%
  {left-transition,left-wall-surface,left-wall-back,left-wall-base,left-wall-tip}
\anchorpage{Platform both: right wall}%
  {platform,platform width=7cm,platform depth=2.5cm,strip width=0.6cm,
   left wall angle=-135,right wall angle=-45,
   left wall inset=0.7cm,right wall inset=0.7cm,
   left wall drop=0.5cm,right wall drop=0.5cm}%
  {right-pulley-center,right-wall-root,right-wall-center}%
  {right-transition,right-wall-surface,right-wall-back,right-wall-base,right-wall-tip}
\anchorpage{Platform left: upward corner}%
  {platform-left,platform width=7cm,platform depth=2.5cm,
   strip width=0.6cm,wall angle=135}%
  {surface,pulley-center,floor-center}%
  {surface,bottom,left,right,wall-surface,wall-back,wall-tip}
\anchorpage{Platform right: upward corner}%
  {platform-right,platform width=7cm,platform depth=2.5cm,
   strip width=0.6cm,wall angle=45}%
  {surface,pulley-center,floor-center}%
  {surface,bottom,left,right,wall-surface,wall-back,wall-tip}
\end{document}