function s = e11v2(m)
% s = e11v2(m): return a $m$-by-$2m$ string matrix $s$ with
% + $*$s on the border (left, right, top, and bottom edges)
% + $\$s on the diagonal, except for on the border
%   (the *diagonal* of a matrix = all valid positions (i,i) in the matrix)
% + $-$s below the diagonal, except for on the border
% + $+$s on the boundary, $@$s in the interior, and $c$ at the center of
%   a disk of radius $round(m*.35)$ and center $(round(m*1.5),round(m/2))$

% version where $x$s are generated from $y$s

n = 2*m; % width of $s$             % [3/14] fixed typo below, where $xc<-->yc$
xc = round(m*1.5); yc = round(m/2); % (yc,xc) = center of disk
r = round(m*.35);                   % radius of disk

% note: deleted definition of coordinate matrices $x$,$y$ from skeleton code

s(m,n) = ' '; % make $s$ large enough
s(:,:) = 'o'; % fill each element with $'o'$

% place $-$s below diagonal: x < y
    for y = 1:m
        for x = 1:y-1;
            s(y,x) = '-';
        end
    end

% place $\$s on diagonal: x = y
    for y = 1:m
        x = y;
        s(y,x) = '\';
    end
    

% place $*$s on border: y = 1, y = m, x = 1, x = n
    % top edge
        y = 1;
        for x = 0*y + (1:n) % or just $1:n$
            s(y,x) = '*';
        end
    % bottom edge
        y = m;
        for x = 0*y + (1:n) % or just $1:n$
            s(y,x) = '*';
        end
    % left and right edges
        for y = 1:m
            % left edge
                x = 0*y + 1; % or just $1$
                s(y,x) = '*';
            % right edge
                x = 0*y + n; % or just $n$
                s(y,x) = '*';
        end

warning('disk not done using this approach')