K-Means

It is a type of unsupervised algorithm which  solves the clustering problem. Its procedure follows a simple and easy  way to classify a given data set through a certain number of  clusters (assume k clusters). Data points inside a cluster are homogeneous and heterogeneous to peer groups.

Remember figuring out shapes from ink blots? k means is somewhat similar this activity. You look at the shape and spread to decipher how many different clusters / population are present!