microcalc = iterative functional javascript  
  
eval the code in the block and write the result as argument for the next iteration
  
(function definitions and arguments are editable)
  
jklm
  

// monte-carlo-pi
(   (  n=0 , t=0 , pi=0 ) =>  [ ++n , Math.random()**2 + Math.random()**2 < 1 ? ++t : t , t/n*4]   )

(   )
  
 

// 1_000_000 × monte-carlo-pi

( (n=0,t=0,pi=0)=>[n=n+1_000_000,t=t+[...Array(1_000_000)].map(()=>Math.hypot(Math.random(),Math.random())<1).reduce((a,b)=>a+b),t/n*4] )

(  )

 
  

// fibonacci sequence

(    (  x=1 , y=0 , ...z ) => [ x + y , x , y , ...z ]   )

(   )

 

// square root

(     ( x=1 , a=prompt() ) =>  [ ( x + a/x )/2 , a ]  )

(     )

// golden ratio

(   x  =>  1 + 1/ x  )

(  1  )

// wurzelgold

(   x =>  Math.sqrt(1+x)  )

(  1  )

// collatz sequence
// try 27 as input

(   (x=prompt(),...z) =>  [ x%2 ? 3*x+1 : x/2 , x, ...z]  )

(   )

(   (x=1) => x+1   )

(   )

// prim numbers

(   ( n , ...z ) => [ n+2 , z.reduce((a,b)=>(n+2)%b*a,1) ? [ n+2 , z ] : z ]  )

(  1, 2  )