Happy SVG:

data:image/svg+xml;base64, PHN2ZyB2aWV3Qm94PSIwIDAgMjAwIDIwMCIgd2lkdGg9IjQwMCIgIGhlaWdodD0iNDAwIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPgogIDxjaXJjbGUgY3g9IjEwMCIgY3k9IjEwMCIgZmlsbD0ieWVsbG93IiByPSI3OCIgc3Ryb2tlPSJibGFjayIgc3Ryb2tlLXdpZHRoPSIzIi8+CiAgPGcgY2xhc3M9ImV5ZXMiPgogICAgPGNpcmNsZSBjeD0iNjEiIGN5PSI4MiIgcj0iMTIiLz4KICAgIDxjaXJjbGUgY3g9IjEyNyIgY3k9IjgyIiByPSIxMiIvPgogIDwvZz4KICA8cGF0aCBkPSJtMTM2LjgxIDExNi41M2MuNjkgMjYuMTctNjQuMTEgNDItODEuNTItLjczIiBzdHlsZT0iZmlsbDpub25lOyBzdHJva2U6IGJsYWNrOyBzdHJva2Utd2lkdGg6IDM7Ii8+Cjwvc3ZnPg==

Sad SVG:

data:image/svg+xml;base64, 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