The Arabic alphabet is always cursive and letters vary in shape depending on their position within a word. Letters can exhibit up to four distinct forms corresponding to an initial, medial (middle), final, or isolated position (IMFI). While some letters show considerable variations, others remain almost identical across all four positions. Generally, letters in the same word are linked together on both sides by short horizontal lines, but six letters (و ,ز ,ر ,ذ ,د ,ا) can only be linked to their preceding letter. For example, أرارات (Ararat) has only isolated forms because each letter cannot be connected to its following one. In addition, some letter combinations are written as ligatures (special shapes), notably lām-alif لا, which is the only mandatory ligature (the un-ligated combination لـا is considered difficult to read).