这是可行的：

vlines, hlines = [], []
# loop over array with clusters to obtain positions of vertical and horizontal lines
for row_idx, row in enumerate(clusters): # loop over array rows
    for col_idx, col in enumerate(row): # loop over array columns per row
        if col_idx+1 < clusters.shape[1]: # skip final column, has no right-side neighbouring node
            # save tuple if it requires a vertical line indicating a different cluster right of the node
            if clusters[row_idx, col_idx] != clusters[row_idx, col_idx+1]: vlines.append((row_idx, col_idx+1))
        if row_idx+1 < clusters.shape[0]: # skip final row, has no bottom neighbouring node
            # save a tuple if it requires a horizontal line indicating a different cluster below the node
            if clusters[row_idx, col_idx] != clusters[row_idx+1, col_idx]: hlines.append((row_idx+1, col_idx))

# make features plot
plt.figure()
plt.pcolor(features, cmap='bone', vmin=0, vmax=1) # color in nodes
plt.colorbar() # make colorbar legend
for vline in vlines: # plot all vertical lines
    plt.axvline(vline[1], ymin=vline[0]/clusters.shape[0], ymax=vline[0]/clusters.shape[0] + 1/clusters.shape[0], color='red')
for hline in hlines: # plot all horizontal lines
    plt.axhline(hline[0], xmin=hline[1]/clusters.shape[0], xmax=hline[1]/clusters.shape[0] + 1/clusters.shape[0], color='red')
plt.show()