two solid surface counter slab,solid surface adhesive,different shape of fixtures,polish machine.
Prepare two slabs and clean the joint side.
Put two slabs together.
Two joint side paint the adhesive.
Use fixture make two slab fixed together.
After 10-15 minutes remove the fixtures,remove the excess glue then polish it by polisher.glossy finish use high NO# sand paper,matt finish use lower No# sand paper.
Last step:clean the joint side then you will find this two slab be joint in seamless and looks like a compeletly one slab.