original.clj

(take 25 (squares-of (integers)))

stream.groovy

@Grab( 'com.bloidonia:groovy-stream:0.5.1' )
import groovy.stream.Stream

// Create a lazy unending stream of integers from 1
def integers = Stream.from { x++ } using x:1

// Create a stream of squares based on this stream of integers
def squares  = Stream.from integers map { it * it }

// Create an Iterator that looks at the first 25 elements of squares
def first25 = squares.take( 25 )

// Collect the elements
assert first25.collect() == [  1,   4,   9,  16,  25,
                              36,  49,  64,  81, 100,
                             121, 144, 169, 196, 225,
                             256, 289, 324, 361, 400,
                             441, 484, 529, 576, 625 ]

be groovier