Skew - gives horizontal and vertical angles of slant. By utilizing simple layer effects, drop shadows, beveled edges, etc. on a selected layer items become possible. Layer effects are especially useful with text. Drop shadow is a particularly useful item. The logo on the top of this .shtml file was given its 3D look using a drop shadow.
Similar options apply for the other layer effects.
See Figure 6. You will get a chance to try these layer effects when we use text in a few minutes. Layers can be combined or all layers can be combined or flattened. This saves available memory and should be done when you are done aligning and working with two or more layers in your document. Flattening should only be done when you have completed your work on a document in Photoshop and no longer wish to work with any of the layers separately.