Summary

New, V2 version, is here:
https://www.thingiverse.com/thing:6721256

Spade made for sandbox.

Feels pretty strong.

One version is easier to use but needs some supports.

You can use some sandpaper after print to round up edges at base.

Print Settings

Printer:

JG Aurora A1

                                            <p class="detail-setting rafts"><strong>Rafts: </strong>                     <div><p>Doesn't Matter</p></div></p>                                                                                <p class="detail-setting resolution"><strong>Resolution: </strong>                     <div><p>0.4</p></div></p>                                                                                <p class="detail-setting infill"><strong>Infill: </strong>                     <div><p>15-20%</p></div></p>                                                    <strong>Filament:</strong> 3D Reaktor PLA                Grey                    <br>                        <p class="detail-setting notes"><strong>Notes: </strong>                    </p><div><p>I used cubic subdivision 20% for infill.</p></div>

Spade for sandbox