Tips: Insert blank cells alternately in Calc

The solution is easier than it seems.

1) Insert ascending numbering in the left column

2) Copy numbers as follows:

3) Select all the data and sort:

4) Sort by the first column with numbers, and then the second, with the original data:

Final result.

Translated from: http://open-galaxio.blogspot.com.es/2014/10/calc-insertar-filas-en-blanco-en-una.html