stack.keys([keys]) If keys is specified, sets the keys accessor to the specified function or array and returns

d3.symbol() Constructs a new symbol generator with the default settings.

d3.symbolTriangle The up-pointing triangle symbol type.

d3.pie() Constructs a new pie generator with the default settings.

pie.value([value]) If value is specified, sets the value accessor to the specified function or number and returns

stack.offset([offset]) If offset is specified, sets the offset accessor to the specified function or array