I unlocked with power-up Missile.
Enter in Single Player mode with this power-up.
Stack blocks on one side only (ex. Left) almost to the top. (leave a gap to put the power up very close to the top.
If the power-up does not show, go putting blocks at right, leaving gaps between the lines to not eliminate them.
When the power-up missile appears, place it to the top left.
Fill out the box and leaving some gaps (spaces) in lines.
When complete the line that has the power up, will have the achievement.