It seems like that clusters appear in very different forms.

A cluster of tiny old men appeared in the doorway.

Time and again a cluster of words had appeared.

Clusters of white flowers appear in late summer to mid autumn.

One cluster of about 30 of the dead, mostly women and children, appeared to have been killed within the past few days.

On the grid platform a cluster of small boxes appeared.

A large cluster of buildings appeared on the horizon.

Clusters of the bracts appear in late spring, while the actual flowers do not develop until early summer.

Scar tapped several keys, and a cluster of symbols appeared.

Suddenly a cluster of huts appears to our front.