span><span class='op'>[</span>, <span class='fl'>2</span><span class='op'>]</span>
<span class='va'>d</span><span class='op'>$</span><span class='va'>t3</span> <span class='op'>&lt;-</span> <span class='va'>time_splines</span><span class='op'>[</span>, <span class='fl'>3</span><span class='op'>]</span>
<span class='va'>d</span><span class='op'>$</span><span class='va'>xq</span> <span class='op'>&lt;-</span> <span class='va'>d</span><span class='op'>$</span><span class='va'>x</span><span class='op'>^</span><