Oh, now I get it! I actually hadn’t realise that I have 4 shards in play -I checked my Index- which get created by the following series of rules:
[code]
Every glass shatters into a pile of broken glassware.
Every bottle shatters into a pile of broken glassware.
Every demijohn shatters into a pile of broken glassware.
Every jug shatters into a pile of broken glassware.
Every pile of broken glassware incorporates a shard.[/code]
(For the ‘shattering into’ relation discussion, see my older thread here.)