A card-pique is a symbol found on playing cards: in non-heraldic terms, a “spade”. Tradition deems it a stylized form of spearhead. The card symbol appears to be period, though not used in period armory. However, there were some types of leaf in heraldry whose depictions are visually indistinguishable from a card-pique – the linden leaf, for instance – and the card-pique is accepted on that basis. It also means no difference is granted from those leaves. See also foil (trefoil), heart, lozenge.
Hugh ap Llewelyn bears: Or, a chevron voided gules between two card-piques and a crux ansata all sable.
Erc FitzMungo bears: Sable, a card-pique argent.
Jacob Maximilian of the Black Forest bears: Quarterly gules and checky argent and sable, a card-pique Or.