Question : Subnetting a subnet

Hi, I've been asked if I can find out the following so I don't have too many details
If you subnet a subnet is it possible for workstations on these two subnets to talk to each other without the need of a router?

Answer : Subnetting a subnet

Yes, if you set the default gateway of each PC to its own IP address, and make sure they are all on the same broadcast domain (VLAN)

But WHY would you want to do that??????