A Morph is the central abstraction of Morphic. The word Morph comes from the Greek for "shape" or "form". A morph is simply a Squeak object that has a visual representation that can be picked up and moved.
In addition, a morph may:
perform actions in response to user inputs;
perform an action when another morph is dropped onto it, or when it is dropped onto another morph;
perform an action at regular intervals; and
control the placement and size of its submorphs.
Composite (sub)morphs
+ Any morph can have component morphs (called submorphs).
+A morph with submorphs is called a composite morph.
The submorphs are said to be "embedded" in the composite morph.
The submorphs can in turn be composite morphs, to any depth.
Each morph can be embedded in at most one composite morph, so the submorph relation defines a tree of morphs.
A composite morph is treated as a single unit: moving, copying, or deleting a composite morph causes all its submorphs to be moved, copied, or deleted as well.
By convention, all morphs are visible; morphic does not use invisible structural morphs for aggregation. This means that if a composite morph is disassembled, all its component morphs can be seen and manipulated.
