Lambda Spiral

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The lambda expression forms a spiral, similar to `[1, 2, 3].map(elem => elem - 1)` in JavaScript. The expression is a complex function that takes another function as an argument and returns a new function that performs the same computation. Here is the lambda expression in ES6 arrow function syntax: ```javascript lt = (f => (x => f(n => x(x)(n)))(x => f(n => x(x)(n))))(m => l => f => (_ => _)((l => l(_ => _ => (_ => f => f(_ => _))))(l))(_ => (_ => (f => _ => f(_ => _))))(_ => (h => t => (l => r => f => f(l)(r))(h)(t))(f((p => p(l => _ => l))(l)))(m((p => p(_ => r => r))(l))(f))))((e => (l => (f => (x => f(n => x(x)(n)))(x => f(n => x(x)(n))))(v => r => l => (_ => _)((l => l(_ => _ => (_ => f => f(_ => _))))(l))(_ => r)(_ => v((h => t => (l => r => f => f(l)(r))(h)(t))((p => p(l => _ => l))(l))(r))((p => p(_ => r => r))(l))))(_ => (f => _ => f(_ => _)))(l))(e(_ => _ => (f => _ => f(_ => _)))))((f => (x => f(n => x(x)(n)))(x => f(n => x(x)(n))))(r => t => h => (_ => _)((n => n(_ => (_ => f => f(_ => _)))(_ => f => f(_ => _)))(h))(_ => t)(_ => r((h => t => (l => r => f => f(l)(r))(h)(t))(h)(t))))(_ => (f => _ => f(_ => _)))(f => x => f(x))(f => x => f(f(x)))(f => x => f(f(f(x))))))(e => (m => n => n(n => (p => p(l => _ => l))(n(p => (l => r => f => f(l)(r))((p => p(_ => r => r))(p))((n => f => x => f(n(f)(x)))((p => p(_ => r => r))(p))))((l => r => f => f(l)(r))(_ => _)(_ => x => x))))(m))(e)(f => x => f(x))); ``` This lambda expression can be used to generate an array of natural numbers, similar to the `natural` function in the code. The `array` function takes the lambda expression as an argument and returns a new array containing the first n natural numbers. Here is an example usage: ```javascript console.log(array(lt)); // show [0, 1, 2] ``` The `natural` function generates a natural number by recursively applying the lambda expression to the current number. The `array` function uses this function to generate an array of natural numbers by repeatedly calling it with the current number and appending the result to the array. Note that the lambda expression is quite complex and difficult to understand without a good grasp of functional programming concepts. However, it provides a concise way to define a recursive function that generates a sequence of natural numbers.