Thinking Activity on Deconstruction

What do you understand by 'Deconstruction'? 
First of all Deconstruction is really a bit difficult to understand, and one reason is that Derrida does not define the Deconstruction. First of all he asks that question that is it possible to define anything once and for all?  Or at what extent can we define something? So he denies to define  deconstruction.
Derrida’s position is more  philosophical than real. He proves theoretically, not practically.
First of all Deconstruction is not a destructive activity, but it is an inquiry into the foundations of every thing. Deconstructionist critics goes deep into the foundation of text and then they try to subvert , undermine it. Derrida says that every text contains element which  can deconstruct itself.

Read an ad or TV serial or Film or literary text as post-structuralist critic. Be brief, precise and to the point.
Here I would like give an example of advertisements of beauty supplements, as ad always shows us the that one person become fairer skin by using particular skin cream, but is there any real incident where we can find that kind of results? obviously no and though we regularly using such supplements.