Kalaimoli type puzzles - a guide

Problem structure and purpose: 

A message will be scrambled vertically. There may be one or more sentences.  Black squares represent the word or sentence ending. These black squares cannot be moved. Only letters need to be moved up or down in the same column, to find hidden messages. 

Important Notes:(For those attempting for the first time)

     1. It looks similar to crossword puzzles which we are familiar with, but is fundamentally very different.

     2. The final answer is read from left to right.

    3. Any letter can only be moved up or down to any place in the same column.  They can even be moved by crossing the black blocks. 

    
Sample problem: 

Let's take a simple example to illustrate the above. 

Below is a jumbled sentence (a nursery rhyme piece) in the form of the puzzle.  The one after this is the original piece, the solution for the puzzle. 

Note for example that the first word "Jack" is formed by shifting J from 3rd row to first row in the first column, a from the second row, etc.