Fibrin clots function primarily to occlude blood vessels to stop bleeding. The maxillary lateral incisors occlude in opposition to the mandibular lateral incisors. This may eventually grow or rupture to occlude the arteries. Non-balanced occlusion is seen when teeth do not occlude in simultaneous contacts. In such cases it may be more appropriate simply to occlude one eye temporarily. Alternatively, riboswitches may bind or occlude the Shine-Dalgarno sequence, affecting translation. Stimulants, most notoriously methylamphetamine, also occlude the flow of saliva to an extreme degree. Their teeth occlude in either an underbite or an end-to-end bite. These teeth do not precisely occlude with one another. The illusion works even when the small squares completely occlude the blue cross (see fig. The Met20 loop of DHFR is able to open, close or occlude the active site. Unlike mammals, the teeth of "Oligokyphus" did not occlude.