\tikzset{
  big triangle/.pic={
  \path[pic actions] (0,0) -- (2,0) -- (2,2) -- cycle;
  },
  medium triangle/.pic={
    \path[pic actions] (0,0) -- (1,1) -- (2,0) -- cycle;  
  },
  square/.pic={
    \path[pic actions] (0,0) -- (1,0) -- (1,1) -- (0,1) -- cycle;
  },
  small triangle/.pic={
    \path[pic actions] (0,0) -- (1,0) -- (1,1) -- cycle;
  },
  parallelogram/.pic={
    \path[pic actions] (0,0) -- (1,0) -- (2,1) -- (1,1) -- cycle;
  }
}

\tikzset{
  tangram puzzle/.style={ fill=black, draw=black },
  tangram solution/.style={ fill=black, draw=white, line width=1mm },   
  tangram/.style={ transform shape,
    %tangram puzzle
    tangram solution
  }
}
