implement alternating blades block

[ramboz]

We need a variant of the blades with less emphasis (no background) and alternating rows.

For instance:

• https://www.delta.com/us/en/skymiles/airline-credit-cards/american-express-business-cards
• https://www.delta.com/us/en/skymiles/how-to-use-miles/buy-gift-transfer-donate-miles