The Flash Bone tool can be used to create an skeleton/armature using symbols

Inverse Kinematics (IK) is a principle relied on computer animation and modeling. Inverse Kinematics determines how jointed or connected objects position themselves relative to one another when moved.

For example, when animating a human arm, if the forearm changes position, it ultimately affects the position of the connected hand and upper arm. These principles help create life-like animation and interaction.

Flash features two tools, Bone and Bind, that you use to connect objects and edit those connections. Connected objects can be posed, and changes between those poses can ultimately be animated. You can create IK relationships between symbol instances or shapes.

Step 1: Create a new Flash document and select ActionScript 3.0

Step 2: Draw an image

Step 3: Convert image Into Symbol

Step 4: Convert Convert the image into a symbol by select the layer and going to Modify/convert to symbol.

Step 5: Select the Bone tool from the Tools panel, move the pointer over the first object until a plus sign appears, drag until the cursor is over the second object, and release the mouse button. This step draws a virtual bone between the two symbols, connecting them. Do the same for the rest of the symbols.

Step 6: Manipulate Armature by using the Selection tool (V) to drag the last bone. The entire armature can now be manipulated in real time as you drag the last bone around. A new keyframe that copies the properties of the previous animation can be created by pressing F6 on your keyboard.  

You can add more objects to the chain. Although you can’t add objects randomly to an Armature layer, you can connect existing IK container objects to artwork on other layers to add them to the chain.

Follow these steps to add objects to an existing armature layer:

Step 1: Create a new layer on the Timeline and drag a symbol instance to it from the Library panel.

Step 2: Position the symbol where you want it relative to the existing IK container objects on the stage.

Step 3: Choose the Selection tool and select in the existing Armature layer the object you want to connect the new symbol to.

Step 4: Choose the Selection tool and drag the new symbol around to see how its motion affects the other objects in the chain.