Vedalken Engineer and Halo Fountain do not have summoning sickness.
Steps
Activate Vedalken Engineer by tapping it, adding ({W} magic symbol) ({W} magic symbol) that can only be spent to cast artifact spells or activate abilities of artifacts.
Activate Halo Fountain's second ability by paying ({W} magic symbol) ({W} magic symbol) , tapping it and untapping Halo Fountain and Vedalken Engineer, causing you to draw a card.