PowerShell pipeline argument binding

pipeline.ps1

function fa {

    [CmdletBinding()]
    param (
        [Parameter(Mandatory,ValueFromPipeline)]
        [int]$x
    )
    # function 1
    BEGIN {Write-Verbose "Begin a: $x"}

    PROCESS {
        Write-Verbose "  Process a: $x"
        # two return values
        2*$x
        3*$x
    }

    END {Write-Verbose "End a"}
}

function fb {

    [CmdletBinding()]
    param (
        [Parameter(Mandatory,ValueFromPipeline)]
        [int]$y
    )
    # function 1
    BEGIN {Write-Verbose "  Begin b: $y"}

    PROCESS {
        Write-Verbose "    Process b: $y"
        # two return values
        $y*$y
        $y*$y*$y
    }

    END {Write-Verbose "  End b"}
}

2,3 | fa -Verbose | fb -Verbose

# Output:
#
# VERBOSE: Begin a: 0
# VERBOSE:   Begin b: 0
# VERBOSE:   Process a: 2
# VERBOSE:     Process b: 4
# 16
# 64
# VERBOSE:     Process b: 6
# 36
# 216
# VERBOSE:   Process a: 3
# VERBOSE:     Process b: 6
# 36
# 216
# VERBOSE:     Process b: 9
# 81
# 729
# VERBOSE: End a
# VERBOSE:   End b