[NTG-context] METAPOST's uniformdeviate is not truly random (seed)

I’m trying to get a real random number in METAPOST MWE: \startMPpage[instance=doublefun] show uniformdeviate 60; \stopMPpage Every time I run this, it shows the same result. I tried playing around with the randomseed, but for instance when I do two runs shortly after each other they still are very predictable. E.g. this in METAPOST: whatever = lua( "math.randomseed( tonumber(tostring(os.time()):reverse():sub(1,6)) )"); randomseed := lua.math.random(); minutespast := uniformdeviate 60; Called shortly after each other (two LMTX runs) gets me the same result. What is a good way to get better random numbers in METAPOST (LMTX)? Thanks, G