A flower limb is a collection of Flowers that are slotted together.
He connects these Flowers to the new one by sliding them inside each other. This is a Flower Limb. He sets it down and watches as everyone gathers at the table, putting their hands on the Flowers, trying them out. With some force they can be slid in and out like a telescope and when they are extended, one Flower can spin on top of another.
..and from Scene 194:
Samuel and Graham play with a couple Flower Limbs. With all their might they collapse and stretch them apart like accordions.
From the first scene, we see for the first time that Samuel's Flower Limb seems to have a life of it's own:
The Limb continues to flex, expanding and contracting on its own.
Unmarked Flower Limbs
The boys find that the initial set of Flower Limbs don't respond to their commands.
Coloured Flower Limbs
Later in the screenplay, the boys decide to mark the flower limbs with Green & Red Markers.
THE GREEN MARKER is brought down the length of a Flower Limb leaving a GREEN STREAK on every single Flower. THE RED MARKER is brought down the length of a Flower Limb leaving a RED STREAK on every single Flower.
They then presumably dismantle the single-coloured flower limbs, and rebuild them as follows:
HANDS connect a Flower with a Green Mark to a Flower with a Red Mark. Then, another Red one is added and so on.
From scene 213 onwards, the Flower Limbs are made from alternating coloured flowers:
We PAN DOWN the length of a COMPLETED FLOWER LIMB. The Flowers' marks alternate RED, GREEN, RED, GREEN, etc.
See also. coloured controllers.