my_lambda = ->(x) { print x }

my_proc = proc { |x| print x }

def my_method(x)
  print x
end

class MyClass
  def self.my_static_method(x)
    print x
  end 
end

nums = Array(1..3)

# using a block
nums.each { |x| print x }

# using a lambda/proc
nums.each(&my_lambda)
nums.each(&my_proc)

#using a method
nums.each(&method(:my_method))

# using a static method
nums.each(&MyClass.method(:my_static_method)) # (1)
nums.each { |x| MyClass.my_static_method(x) } # same as (1)