House of Cards Solitaire 6.0

The purpose of this computer game is to build a house of cards with smaller pairs on top.
The game offers 20 and 21 as special cards.
To make a pair, click 2 cards of the same suit or value. To build higher, place any card as a "beam".
Pairs must be supported by pairs with equal or larger values, or pair will crumble. Beams can be any value.
20 can be placed anywhere. 21 reinforces below. Blow Joker blows down one level. 2 Blow Jokers end game.