The term "spatial tense" is mostly employed in the grammar of Lojban (an artificial language). In Lojban, temporal and spatial tense are treated alike. When present, they are marked by particles, which may appear in different parts of the sentence according to the emphasis the speaker wants to convey. The spatial tense morphemes show position and/or distance relative to the speaker. The difference between spatial tense and the use of words and phrases like "here", "to the left", "at a short distance ahead", etc., lies in the fact that these phrases are simply lexical items, while spatial tense is a grammatical category of the verb (more properly speaking, the predicate).