Omni-directional drive

[Caution Man]

My team's been addled with an argument concerning omni-directional drive. Some of the team-members believe that it's possible to create an omni-diretional drive system (meaning, it's capable of strafing) using omniwheels (not mech wheels) in a normal tank-drive configurations (all the wheel's turned straight). We've heard that omnidirectional driving can be done with omniwheels by turning them at an angle, but some team-mates don't think that this is necessary. We've had trouble finding internet resources that would give us an explicit yes or no answer (using straight omniwheels in a normal tank drive configuration to strafe; can or cannot be done), so we were wondering if anybody on this forum could settle the matter for us.

For a final bit of clarification, our omni-wheels would look like this = =, and we want to strafe. Sorry if I've repeated myself, I just want to communicate clearly. Please include any references so that we may refer to those as well.