If we have a skip of 3, then:
The social network said its members had expressed concerns that they were missing 'important updates' from the people they cared about.
T cleo ii mrh psdoesh eweii mrnuasfmhpp eceauT cleo ii mrh psdoesh eweii mrnuasfmhpp eceauT cleo ii mrh psdoesh eweii mrnuasfmhpp eceau
For example if we have plain text of "01234567", with a jump of 3 we get:
Now we take "epnlhtea", and match:
Let's take the first three charactersof 0, 1 and 2, which are e, l and e:
Next 3, 4 and 5, which are p, h and a:
Finally for 6 and 6, which are n and t