Hello)
I got the source code of Surge smart asset from node info about it

# Surge is a Smart Asset.
# It's price is increased every day: it is at least 0.001 * (1 + days * days) WAVES.
# DEX orders should have expiration less than 100 minutes.
let startHeight = 1375557
let startPrice = 100000
let interval = 24 * 60
let exp = 100 * 60 * 1000
match tx {
case e:ExchangeTransaction =>
let days = (height - startHeight) / interval
if (
if (
if (
e.price >= startPrice * (1 + days * days)
)
then
!isDefined(e.sellOrder.assetPair.priceAsset)
else
false
)
then
exp >= e.sellOrder.expiration - e.sellOrder.timestamp
else
false
)
then
exp >= e.buyOrder.expiration - e.buyOrder.timestamp
else
false
case tx:BurnTransaction => true
case _ => false
}