Error using bar when plotting from variables

I'm trying to plot with the following code:

w1 = 0.5;
x = [1 2 3 4]
y1 = [C1a, C1d, C2a, C2d]
y2 = [C1aO, C1dO, C2aO, C2dO]
bar([x, y1, w1, 'FaceColor',[0.2 0.2 0.5]])
ax = gca;
ax.YLabel.String = "Capacity"
title('Needed Capacity')
w2 = 0.7;
hold on
bar(x,y2 ,w2, 'FaceColor',[0 0.7 0.7])
hold off

Which gets me the stated error. I tried several things like removing ",", etc. but can not figure out where I am going wrong - a hint would be very much appreciated!

Edit:

[C1a, C1d, C2a, C2d] = [1, 2, 3, 4]

[C1aO, C1dO, C2aO, C2dO] = [0, 1, 2, 3]

Answer 1

[Rik]

bar([x, y1, w1, 'FaceColor',[0.2 0.2 0.5]])
%   ^                                    ^

Those brackets are incorrect.