import matplotlib.pyplot as plt
import numpy as np
a = np.array([[1,1,1],[1,0,1],[0,1,0]])
print(a)
af = np.flipud(a) ### flip upside down, get the right coordinates in the scatter plot
args = np.argwhere(af) ### find the args where we do not have zeros
plt.figure(figsize=(3,3))
plt.scatter(args.T[1,:],args.T[0,:], marker="x"); #plot!
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