Carbon signals point up or down by whether they carry an odd or even number of protons.
Checked against S. L. Patt, J. N. Shoolery, J. Magn. Reson. 46, 535–539 (1982), doi:10.1016/0022-2364(82)90105-6; Bruker pulse program jmod.
Process NMR spectra in NMRium and draw pulse sequences, from a library of standard experiments or column by column, and save both as figures that open again. The site needs JavaScript, because every spectrum and figure is handled in your browser.