This encyphered engineering book is interesting, maybe?

[MarcoP]

About those vertical, slender constructions, what are they even? It looks like they each have a flame on top, so maybe lamp stands like you'd find in an Italian palace?

They remind me of the Sforza hours

Looking again they seem to be around cannons, and also columns. Maybe Marco can enlighten us?
(Pages 59,60 and 91)

I cannot add much to what others wrote above. The Florentine Bonaccorso Ghiberti was descended from the much more famous You are not allowed to view links. Register or Login to view., whose bronze workshop he presumably inherited. His notebook appears to mostly be about bronze works.

You are not allowed to view links. Register or Login to view. describes similar vertical objects as “candelabra”, though I cannot see any candles, so “lamp stands” as suggested by Koen could be a better term. Given their shape, the objects were often used to fill vertical space as decorations, but I think Bonaccorso was designing actual objects to be cast in bronze. The text in the margins of f.91r is unrelated; it’s about the two “rockets” (“razzi”) also illustrated in the margin, I am not sure if these are meant as mere fireworks or for military usage.

56r appears to be an architectural detail, possibly for the building on the previous page.
The text in cipher and plaintext says where the details are meant to be placed and gives a few measures.

The knight’s tomb belongs to the tradition of monuments to military leaders derived from the bronze statue of Marcus Aurelius. The 1436 fresco portrait of Giovanni Acuto (John Hawkwood) is by Paolo Uccello, who began his artistic career in Lorenzo Ghiberti’s workshop.