There are three kinds of directionality. The first is the direction of the sentence.
The second is the left/right direction of its letters or glyphs, and the third is their degree of rotation.

The direction of an English sentence is written from left to right, starting at the top and going down. 
This paragraph is an example of that. English letters only face in one direction. 
They do not have any degree of rotation.

In contrast, Ancient Egyptian is one of the few writing systems which can be written in more than 
one direction. It was usually written from right to left. Here is a an example line of Hieratic from a 
tomb robbery papyrus.

Cartouche in Hieratic
but Hieroglyphs could also be written from left to right,


or they could be written from top to bottom. Here is an example in Hieratic taken from the story of
the shipwrecked sailor.

From: Story of the Shipwrecked Sailor

Secondly, Hieroglyphs themselves were placed to face in the direction of the main charactor as
well as placed to satisfy considerations of  symmetry and artistry.

                    Left to Right and Right to Left Hieroglyphs

Below is a picture which illustrates many of these principals.  One can also see from the left and 
right panels of this false door how the writing proceeds from top to bottom, and from the center 
panel how it proceeds from one side to the other. The white arrows indicate the direction in 
which the glyphs are placed.

False Door Stele of Itete

Early 6th Dynasty
(2323-2152 BC)
JE 15157

On this false door discovered by Mariette in 
Itetiís mastaba at Giza (1861), the deceased is 
portrayed on the uprights together with his
titles, and in the door opening , where he is 
portrayed in half-relief.

Source: Page 83.The Treasures of 
Tutankhamun and the Egyptian Museum 
of Cairo VMB Publisers 
Copyright 2005,2007 

Hebrew was and is also written from right to left. Here is an example taken from the Siloem Inscription.
Siloem Translation

The third occurs when glyphs are flipped on their horizontal axis, are rotated 45 or 90 degrees, 
or are part of a complex glyph. When this happens the glyph can take on a different meaning. 
Here are some examples taken from glyphs listed on the "Hieroglyphica" website.

Hieroglyphica OneHieroglyphica TwoHieroglyphica ThreeHieroglyphica FourHieroglyphica FiveHieroglyphica SixHieroglyphica Seven

    Z25        Z25A        Z25B        A30    A100        A101    A101B       

Hieroglyphica EightHieroglyphica NineHieroglyphica TenHieroglyphica ElevenHieroglyphica Twelve
    D47        D271        D54        D287     D292