to obstruct - a) to block or stop up (a passage) with obstacles or impediments; to clog; b) to hinder (progress, an activity, etc.); to impede.

to spread out oneself in all direction and widely; to diffuse oneself.

to cause to come back, happen again.

to rotate - a) to turn around or cause to turn around a centre point or axis; b) to go or cause to go in a regular and recurring succession of changes; to take or cause to take, turns.

to re-examine; to review again.