[chuankl]

IIRC on ThinkPad keyboards, the 6-key navigation block (arrow keys + pgup & pgdn) has a lower baseline -- the bottom of the block is lower than the bottom of the rest of the keys on the keyboard. So it is still easy to find the arrow keys by touch, even without blank space above the left and the right arrow keys.

[tadfisher]

There is also a tactile nub on the Down key, so it's trivial to find it wiith your middle finger and go to town.