Landscape is currently only supported for tablets and not phones. If you are playing on an iPhone you cannot rotate into landscape at this time. If you are reporting that the application does not rotate to fill the entire width of the display when the device it rotated to landscape orientation, then there are a couple of options to check.

1. Your device may be locked in the portrait orientation. To check this setting follow this link as it varies by iOS version: https://support.apple.com/en-us/HT204547

2. The game settings may be preventing you from rotating the device. Go to the settings in the game and check to see if the settings show full-size table as on. If this setting is turned on the puzzle will be locked in the orientation in which it was started. Updating this setting will not go into effect until the next puzzle is started.