graf 4*log2(x) is strateforward provided yu kan get log tu base 2
log2(1)=0
log2(2)=1
log2(3)=1.5849625007
tu get this, log10(2)=0.301029995
log10(3)=0.477121254
log2(3)=log10(3)/0.30102995
or log2(x)=(1/0.301029950)*log10(x)
log2(x)=3.321928135* log10(x)