Can't save data using push button (MATLAB) - function

Question

I'm trying to create a figure where the user can select cells to turn on or off. Then, the user can click a button 'Enter' to save the board as an array. I successfully found a way to create interactivity in my plot thanks to a very useful explanation I found here. I just made some changes to suit my needs.
However, I can't find a way to save the board. The button is working (or at least isn't not working), but the data isn't saved. And I don't know how to fix that. Any help would be appreciated.
Here is my code:
function CreatePattern
hFigure = figure;
hAxes = axes;
axis equal;
axis off;
hold on;
% create a button to calculate the difference between 2 points
h = uicontrol('Position',[215 5 150 30],'String','Enter','Callback', #SaveArray);
function SaveArray(ButtonH, eventdata)
global initial
initial = Board;
close(hFigure)
end
N = 1; % for line width
M = 20; % board size
squareEdgeSize = 1;
% create the board of patch objects
hPatchObjects = zeros(M,M);
for j = M:-1:1
for k = 1:M
hPatchObjects(M - j+ 1, k) = rectangle('Position', [k*squareEdgeSize,j*squareEdgeSize,squareEdgeSize,squareEdgeSize], 'FaceColor', [0 0 0],...
'EdgeColor', 'w', 'LineWidth', N, 'HitTest', 'on', 'ButtonDownFcn', {#OnPatchPressedCallback, M - j+ 1, k});
end
end
%global Board
Board = zeros(M,M);
playerColours = [1 1 1; 0 0 0];
xlim([squareEdgeSize M*squareEdgeSize]);
ylim([squareEdgeSize M*squareEdgeSize]);
function OnPatchPressedCallback(hObject, eventdata, rowIndex, colIndex)
% change FaceColor to player colour
value = Board(rowIndex,colIndex);
if value == 1
set(hObject, 'FaceColor', playerColours(2, :));
Board(rowIndex,colIndex) = 0; % update board
else
set(hObject, 'FaceColor', playerColours(1, :));
Board(rowIndex,colIndex) = 1; % update board
end
end
end
%imwrite(~pattern,'custom_pattern.jpeg')