Keep the radial design as a SmartArt graphic until you're done adding new shapes. Once you've converted it to shapes, the new radial elements won't be added automatically. If you have other items ...

Learn how to add Morph transition in PowerPoint. Morph animate movements from one slide to the next. Morph one shape into another in PowerPoint.

You can create hand-drawn shapes and add a chalk effect in PowerPoint. You can make a flowchart, circle, or any picture using this method.

Now, when selecting Preview on the Animations menu, you can see the mouse move from the green triangle to the red triangle along the path specified. Obviously, the animation isn't unique to PowerPoint ...

When a shape doesn't spin in a circular motion as expected in Microsoft PowerPoint, consider where the shape's axis of rotation is. You might need to force a new one.

PowerPoint 2007 has WordArt tools that let you generate text not only in a half-circle, but in all sorts of rings, waves, slants and fades so you can morph your words into whatever shape you envision.