USA, Switzerland and Australia are examples of  coming together federations. India, Belgium and Spain are examples of  holding together federations. 'Coming together' federation is nothing but independent states coming together on their own to form a bigger state or country. Holding together federation is nothing but the division of powers between the states of the country and central government of that country. All the constituent States usually have equal power and are strong vis-à-vis the federal government in coming together federation. The central government tends to be more powerful vis-à-vis the States in holding together federation.