We are starting to receive details in regards to dissecting the BlackBerry 10 OS, this OS is like no other, very unique. If you watch the video below and see how everything flows smoothly, you either drag up or down depending if you want to accept or reject the call. See the video yourself:
As GagdetMasters state:
This BlackBerry Z10 is NOT running final software, and does NOT have final hardware. The final phone app revealed on January 30th could look different.
Source: GadgetMasters