For Isaac's 3 year old version I cut out a shamrock shape from an old cereal box. Then Isaac tore pieces of green construction and tissue paper and glued them to the cardboard. We happened to have some gold sparkly puffy paint, so Isaac put some on...and spread it around with a paint brush. We're hoping the gold sparkles attract some Leprechauns to come for a visit!
For the 1 year old version I drew a shamrock shape on a piece of contact paper. We gave Amy some pieces of paper Isaac had torn and encouraged her to stick them to the sticky side of the contact paper.