\documentclass{standalone}
\standaloneconfig{border=2mm 2mm 2mm 2mm}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usetikzlibrary{calc}

\begin{document}

\begin{tikzpicture}[scale=1.00]

    \fill[black!20!white,dashed] (-1,1) rectangle (1,-1);
    \draw[dashed] (-1,1) rectangle (1,-1);
    \draw[->] (-2.5,0) -- (2.5,0) node[right] {$x$};
    \draw[->] (0,-2.5) -- (0,2.5) node[above] {$y$};
    \node[above right] at (1,-0.02) {\small 1};
    \node[below left] at (0,0) {\small 0};
    \node[above left] at (-0.02,1) {\small 1};
    \node[above right, font=\small] at (0,1) {$B_{\infty}(0,1)$};
    \fill (0,0) circle[radius=1.5pt];


    \draw[dashed, fill=black!20!white] (4,3) circle [radius=0.75cm];
    \draw[->] (2.5,3) -- (5.5,3) node[right] {$x$};
    \draw[->] (4,1.5) -- (4,4.5) node[above] {$y$};
    \node[above right] at (4.75,2.98) {\small 1};
    \node[below left] at (4,3) {\small 0};
    \node[above left] at (4,3.75) {\small 1};
    \node[above right, font=\small] at (4,3.75) {$B_{2}(0,1)$};
    \fill (4,3) circle[radius=1.5pt];


    \fill[black!20!white] (-5,3) -- (-4,4) -- (-3,3) -- (-4,2) -- cycle;
    \draw[dashed] (-5,3) -- (-4,4) -- (-3,3) -- (-4,2) -- cycle;
    \draw[->] (-5.5,3) -- (-2.5,3) node[right] {$x$};
    \draw[->] (-4,1.5) -- (-4,5) node[above] {$y$};
    \node[above right] at (-3,3.02) {\small 1};
    \node[below left] at (-4,3) {\small 0};
    \node[above left] at (-4,4) {\small 1};
    \node[above right, font=\small] at (-4,4) {$B_{1}(0,1)$};
    \fill (-4,3) circle[radius=1.5pt];


\end{tikzpicture}

\end{document}