More diagrams! In the top one, the straight line is a physical screen. The jagged line is Surplus, approaching the Pearls amiably, being turned down by various functionaries in his attempt to arrange a meeting with the Duke of Muscovy, and then chatting with the Pearls a second time. The first chat results in this (telescoped) exchange:
When do we meet our bridegroom?
We are anxious to . . . make him happyThe second chat results in Surplus being told: You have no idea how much trouble we can make.
The second diagram I cannot explain unless it is a first attempt to block out Zoësophia's flirtation with the poet whose name she cannot be bothered to remember. But that happens in chapter five, so maybe not.